Block E: Electrical and comfort control Flashcards
1
Q
Which specific gravity reading taken at 20 degrees C, would indicate that a lead acid battery was fully charged?
a. 1.100.
b. 1.165.
c. 1.225.
d. 1.265
A
d. 1.265
A 100% charged lead acid battery should produce a specific gravity reading of positive 1.265 at 20 degree C.
2
Q
After performing a hydrometer test on a fully charged battery, cell 1 has a specific gravity of 1.279 and cell 2 has a specific gravity of 1.225. What should be done with this battery?
a. Recharge and test.
b. Return to service.
c. Replace.
d. Replace electrolyte.
A
c. Replace.
Because the variation between the specific gravity in the two cell is greater than 0.050 on a fully charged battery, the battery should be replaced.
3
Q
A heater fan is not working correctly in a vehicle. It was replaced with a new motor but still does not have adequate speed. What tests should the tech perform with a DVOM to determine the circuit problem?
a. Check voltage drops in the circuit, then
check for current draw.
b. Check resistance of the motor, then
check for current draw.
c. Check voltage at the motor, then test
grounds.
d. Check the grounds for the circuit, then
test voltage at the motor.
A
a. Check voltage drops in the circuit, then check for current draw.
4
Q
A tech is checking a no-crank condition on a vehicle. After installing an appropriate test meter, the tech notes an extremely large draw and the cables from the battery to the starter seemed to jump. What would cause this condition?
a. The starter has shorted hold-in windings.
b. The starter has an open field winding.
c. The engine is seized or is mechanically
locked.
d. The resistance in the starting circuit is
high.
A
c. The engine is seized or is mechanically locked.
5
Q
The fuel pump keeps running after the ignition key is switched off. What could cause this?
a. Oil pressure switch is grounded out.
b. Fuel pump relay contacts are stuck
closed.
c. PCM fuel pump control is grounded.
d. Fuel pump relay control open.
A
b. Fuel pump relay contacts are stuck closed.
6
Q
The hazard warning lights do not flash when the switch is activated. The signal lights work normally. The same bulb is used for both circuits on this lighting system. What causes this problem?
a. A faulty ignition switch
b. A fault in the signal light flasher
c. A fault in the signal light wiring
d A faulty hazard flasher
A
d. A faulty hazard flasher
7
Q
While diagnosing an inoperative power window, a tech notes that the passenger side power window will operate in one direction only (down). What component failure would cause this?
a. Circuit breaker
b. Regulator
c. Window switch
d. Window motor.
A
c. Window switch.
8
Q
A trailer with electric brakes is being diagnosed for poor brake application when loaded. The tech has set the gain on the controller correctly and confirmed that power is available at the trailer’s wheels. How should the tech proceed to determine the fault?
a. Measure the current flow in the brake circuit to each wheel to verify the connections are secure.
b. Check resistance of the magnets and
compare them to each other.
c. Monitor the brake controller voltage and
replace the magnets at each wheel.
d. Check the polarity of the magnets with a
compass to verify operation of each
wheel.
A
a. Measure the current flow in the brake circuit to each wheel to verify the connections are secure.
9
Q
Which statement is true for gauge type or warning lamp systems?
a. When a balancing coil gauge indicates a
high reading, the sending unit will have
low resistance.
b. If all warning gauges in the instrument
cluster read right, the cause is a shorted
ground.
c. When a balancing coil gauge indicates a
high reading, the sending unit will have
high resistance.
d. If all warning gauges in the instrument
cluster read high, the cause is a shorted
feed.
A
c. When a balancing coil gauge indicates a high reading, the sending unit will have high resistance
10
Q
Which statement is correct for boost charging a dead battery?
a. The negative cable should be
connected to the charged battery last.
b. The positive cable should be connected
to the charged battery first.
c. The negative cable should be
connected to the dead battery first.
d. The positive cable should be connected
to the charged battery last
A
b. The positive cable should be connected to the charged battery first.
+ to dead vehicle’s battery positive
+ to running vehicle’s battery positive.
- to running vehicle’s negative and
- to dead vehicle’s engine block
11
Q
What is the correct sequence for starting system testing?
a. Perform alternator tests, then test
battery voltage.
b. Perform a battery test, then test starter
draw.
c. Remove the starter from the vehicle,
then test the battery.
d. Test the hold-in and pull-in windings,
then test the armature.
A
b. Perform a battery test, then test starter draw.
12
Q
When performing heat shrink tubing repairs, what is the correct procedure?
a. Repair a fusible link, then apply the
shrink tubing.
b. Solder the wires, then position the
tubing and apply heat.
c. Cover an insulated butt splice, then tape
the wire.
d. Strip the wire, then apply the shrink
tubing to the copper.
A
b. Solder the wires, then position the tubing and apply heat.
13
Q
When replacing an instrument cluster, what precautions must be followed on installation?
a. Replace all fasteners and torque them
specification.
b. Install a static strap, then remove the
cluster from the anti-static bag.
c. Reset the odometer, then record it on
the work order.
d. Remove the lens on the gauge cluster,
then coat it with anti-static spray.
A
b. Install a static strap, then remove the cluster from the anti-static bag.
14
Q
A tech checks a CCFOT air conditioning system notices that the low side pressure is 26 psi, and the high side is 210 psi. Discharge air from the vent is 14C. What is the problem in the air conditioning system?
a. Plugged evaporator
b. Temperature blend control door
malfunction
c. Plugged condenser
d. Air distribution control door malfunction.
A
b. Temperature blend control door malfunction.
15
Q
The tech installs A/C gauges and operates the air conditioning system. The following readings and symptoms are noted. what is the cause of the problem? High side 210 psi Low side 45 psi Compressor cycle time 10 seconds on and then 4 seconds off a. Faulty compressor b. Plugged condenser c. Plugged evaporator d. Incorrect oil in refrigerant.
A
c. Plugged evaporator.
16
Q
What is indicated when the ambient air temperature is 21C, and the pressure of the refrigerant in the storage bottle is 78psi?
a. Normal condition
b. The bottle is overcharged
c. The bottle is undercharged
d. The refrigerant is a contaminated “cocktail”.
A
d. The refrigerant is a contaminated “cocktail
17
Q
A customer complains of a lack of heat. The tech notices that engine operating temperature is correct and the lines to and from the heater core are hot. What is causing the problem?
a. Low coolant level
b. Radiator cap pressure too high
c. Air lock in the heater core
d. Temperature blend door malfunction.
A
d. Temperature blend door malfunction.
18
Q
A vehicle at 915 m above sea level has a weak radiator cap that can only maintain 1.5 psi of pressure. If the coolant is mixed 50/50, what temperature will the coolant boil?
a. 100C
b. 97C
c. 107C
d. 125C
A
c. 107C
19
Q
What is the correct procedure to remove odour from an AC system?
a. Remove the air box, then spray deodorizer onto the evaporator.
b. Remove the air box, then steam clean the evaporator.
c. Remove the air box, then sanitize the evaporator.
d. Remove the heater fan motor, then spray deodorizer on the evaporator.
A
c. Remove the air box, then sanitize the evaporator.
20
Q
Which statement is true when repairing or servicing an air conditioning system?
a. A/C systems are evacuated to remove moisture and air from the system.
b. A/C systems are recharged by adding refrigerant according to discharge temperature.
c. Refrigerant recovery of A/C systems is used to reduce customer costs.
d. The labels attached to A/C systems always indicate the correct refrigerant in the system.
A
a. A/C systems are evacuated to remove moisture and air from the system.
21
Q
A cooling system is being checked for coolant contamination. The antifreeze is cloudy. What should be done?
a. Test for pH levels, then add a suitable additive package.
b. Drain and flush the system, then add new coolant.
c. Test for electrical conductivity, then add coolant until it meets specifications.
d. Add acid to clean the system, then replace the pH balanced coolant.
A
b. Drain and flush the system, then add new coolant.
22
Q
Which of the following test would be most effective in identifying the location of high resistance in a starting circuit?
a. Resistance test with an ohmmeter.
b. Current draw test with an ammeter.
c. Voltage drop test with a voltmeter.
d. Check OBD 11 fault codes.
A
c. Voltage drop test with a voltmeter.
23
Q
WHICH OF THE FOLLOWING SHOULD BE TRUE WHEN JUMP-STARTING A CAR WITH A DEAD BATTERY WITH ANOTHER VEHICLE?
a. The last connection should be ground on the dead vehicle.
b. The first connection should be positive on running vehicle.
c. The last connection should be positive on running vehicle.
d. The first connection should be ground on the dead vehicle.
A
Answer is a. \+ to dead vehicle > \+on running > – on running vehicle > - on dead vehicle.
24
Q
A starter motor will not crank, and the vehicle headlamps remain bright. Which of the following could account for this condition?
a. Corroded battery-positive terminal.
b. Corroded battery-negative terminal.
c. Field coils in starter shorted to ground.
d. Defective neutral safety switch.
A
d. : Defective neutral safety switch.
25
A starter motor will not crank, and the vehicle headlamps dim when the ignition circuit is energized. Which of the following should be checked first?
a. Discharged battery.
b. Corroded terminals.
c. Field coils in starter shorted to ground.
d. Armature shorted to ground
a. Discharged battery.
26
When checking starter current draw with an inductive ammeter clamp, which of the following should be done?
a. Disconnect the battery ground terminal.
b. Disconnect the alternator.
c. Crank the engine.
d. Run the engine at idle speed
c. Crank the engine.
27
What is the maximum voltage drop for any given wire connection on an alternator?
a. 0.2 V-DC.
b. 0.5 V-DC.
c. 1.0 V-DC.
d. 1.5 V-DC
a. 0.2 V-DC
28
What would be the likely result of a poorly grounded voltage regulator?
a. Discharged battery.
b. Burned out alternator.
c. Arcing noise in alternator.
d. Excessively high charging voltage.
d. Excessively high charging voltage
29
Which of the following is being done to an alternator when battery voltage is applied directly to the field terminals?
a. Shorting.
b. Full-loading.
c. Full-fielding.
d. Zero-loading
c. Full-fielding.
30
When setting up to test the amperage output of an alternator, where should the clamps of a carbon pile tester be located?
a. Battery positive and battery negative.
b. Alternator B+ and ground.
c. Alternator B+ and Alternator F
terminal.
d. Starter motor positive and alternator
B+
a. Battery positive and battery negative
31
Where should the leads of a DVOM be placed to check for excessive key-off current drain using an ohmmeter on a vehicle battery?
a. Disconnect battery ground and check between main ground terminal and chassis.
b. Disconnect battery positive cable and check between it and chassis.
c. Suspected current drain cannot be checked with an ohmmeter.
d. Disconnect alternator Battery + and check between it and chassis.
b. Disconnect battery positive cable and check between it and chassis.
32
The air conditioning system controls humidity by:
a. Drying the air
b. Warming the air
c. Pressurizing the air
d. Melting frost
a. Drying the air.
33
What is "ambient temperature"?
a. Refrigerant temperature
b. Desired passenger compartment temperature
c. Passenger compartment temperature with system off
d. Air temperature outside the vehicle.
d. Air temperature outside the vehicle
34
To what percentage of its capacity can a refrigerant container be filled?
a. 100
b. 90
c. 60
d. It depends on the refrigerant type
c. 60.
35
Heat that is added to a substance which does not result in a temperature change is:
a. Wasted
b. Sensible
c. Specific
d. Latent
d. Latent
36
High-pressure refrigerant is cooled below its boiling point in the:
a. Evaporator
b. Compressor
c. Condenser
d. Accumulator
c. Condenser.
37
You are monitoring a compressor clutch coil circuit with a voltmeter and notice a large voltage spike in the control wire every time the coil is de-energized. What should you test next?
a. Nothing, this is normal
b. Compressor diode
c. Compressor coil
d. Compressor switch
b. Compressor diode.
38
Temperature control is achieved in some systems by moving the:
a. Mode door
b. Recirculation door
c. Bi-level door.
d. Blend door
d. Blend door.
39
Which of the following is a part of the low side of the air-conditioning system?
a. Receiver-drier
b. Condenser
c. Evaporator
d. Compressor outlet
c. Evaporator.
40
Pressure on the refrigerant is reduced at the:
a. Expansion valve
b. Accumulator
c. Reed valve
d. Receiver-drier
a. Expansion valve
41
Pistons in the axial-type compressor are driven by:
a. A driveshaft
b. A crankshaft
c. Elliptical lobes
d. A swashplate
d. A swashplate
42
The purpose of the compressor clutch diode is to:
a. Turn the clutch on and off
b. Suppress voltage spikes
c. Prevent overheating of the compressor
d. Provide high voltage for activation
b. Suppress voltage spikes
43
The size of the expansion valve orifice is controlled by:
a. Evaporator temperature
b. Condenser pressure
c. Compressor outlet pressure
d. Refrigerant flow through the accumulator
a. Evaporator temperature
44
In a fixed-orifice tube system, refrigerant flow is controlled by:
a. Cycling the compressor clutch
b. Adjusting the pintle valve
c. Throttling the suction line.
d. Regulating the accumulator bypass
a. Cycling the compressor clutch
45
The high-pressure relief valve typically opens at:
a. 150 to 200 psi
b. 250 to 300 psi
c. 350 to 400 psi
d. 450 to 550 psi
d. 450 to 550 psi
46
The power-steering pressure switch turns the air-conditioning compressor off:
a. When the power-steering belt breaks
b. During high speed maneuvering
c. In stop-and-go traffic
d. During parking maneuvers
d. During parking maneuvers
47
If a blower does not operate at any speed, first check the:
a. Resistor
b. Relay
c. Switch
d. Fuse
d. fuse
48
Evacuating removes water from the air-conditioning system by:
a. Boiling it
b. Condensing it
c. Mixing it with the oil
d. Pulling it into the desiccant
a. Boiling it
49
Which of the following is NOT a recommended method of determining correct refrigerant charge?
a. Refrigerant weight
b. Sight-glass appearance
c. Refrigerant volume.
d. System pressures
c. Refrigerant volume.
50
Frost on high-side refrigeration fittings may indicate:
a. Too much lubrication oil in the system
b. Restriction in the system
c. Compressor failure
d. Low refrigerant level
b. Restriction in the system
51
The outlet line from the evaporator should be:
a. Hot
b. Warm
c. Cool
d. Frost-covered
c. cool
52
If both the low side and the high side show low readings, what might be the problem?
a. Low refrigerant charge or leaks
b. Condenser malfunction
c. Cooling fan malfunction
d. TXV stuck open
a. Low refrigerant charge or leaks
53
The most common cause of compressor failure is:
a. Belt failure
b. Contaminated refrigerant
c. Insufficient lubrication
d. Clutch failure
c. Insufficient lubrication.
54
Which of the following is true when refrigerant leaves the compressor in an A/C system?
a. Low-pressure liquid.
b. Low-pressure gas.
c. High-pressure liquid.
d. High-pressure gas.
d. High-pressure gas.
55
What oil(s) must be used in automotive HFC-134a air-conditioning system?
a. PAG only
b. Mineral oils only.
c. Ester only.
d. PAG and ester in R-12 retrofit systems
d. PAG and Ester in R-12 retrofit sys.
56
In which of the following components is refrigerant boiled to a vapour?
a. Compressor.
b. Evaporator.
c. Dryer.
d. Condenser
b. Evaporator.
57
In a 3-position A/C stem valve, what is the normal operating position?
a. Front-seated.
b. Mid-position
c. Back-seated.
d. Open
c. Back-seated.
58
When evacuating a HFC 134a A/C system, how long should the vacuum reading be held at 29.9 (76 cm) of Hg (mercury)?
a. 30 minutes
b. 15 minutes.
c. 10 minutes.
d. 5 minutes
a. 30 minutes
59
What type of HFC 134a leak-detection method is most accurate in detecting the smallest leaks?
a. Fluorescent leak tracer.
b. Electronic leak detector.
c. Flame-type propane leak detector.
d. Soapy water solution.
b. Electronic leak detector.
60
Which of the following is a likely indication of low refrigerant charge in a HFC 134a A/C system?
a. Compressor damage.
b. Higher than normal gauge readings.
c. Noisy compressor operation.
d. Faster than normal clutch switch cycling
d. faster than normal clutch switch cycling
61
Which of the following HVAC control doors determine whether ventilation air flows through the heater core?
a. Mode door.
b. Defroster door.
c. Blend door.
d. Heater door
c. Blend door.
62
When replacing a starter that can be shimmed, what is the necessary clearance between the flywheel and the starter pinion?
a. 1/16” (1.59mm)
b. 1/8” (3.18mm)
c. 3/16” (4.76mm)
d. 1/4” (6.35mm)
b. : 1/8” (3.18mm)
63
When cranking an engine, the starter motor turns over slowly. Which of the following is a probable cause?
a. Neutral safety switch.
b. Worn starter bushings.
c. Low resistance in the negative cable.
d. Excessive battery CCA
b. Worn starter bushings.
64
A starter motor will not crank, and the headlamps dim when the starting circuit is energized. The battery test is acceptable, and the connections are corrosion-free. Which of the following should be checked next?
a. Positive battery cable for an open circuit.
b. Neutral safety switch for high resistance.
c. Ignition switch for high resistance.
d. Starter mounting for flange corrosion
d. Starter mounting for flange corrosion.
65
Which of the following is an acceptable maximum AC voltage leakage output from an alternator in a normal load condition?
a. 0.5 -1.0 V-AC.
b. 0.1 – 0.5 V-AC.
c. 1.0 – 1.5 V-AC.
d. 13.5 _ 15.5 V-AC
b. 0.1 – 0.5 V-AC.
66
Which of the following could cause excessive alternator whine?
a. No load operation.
b. Defective diodes.
c. Defective rear bearing.
d. Glazed belt
b. : Defective diodes.
67
What is the purpose of using a carbon pile in a charging system diagnostic routine?
a. Test the battery specific gravity.
b. Load the battery to initiate alternator to maximum output.
c. Bypass the PCM control.
d. Test wiring for opens and shorts
b. Load the battery to initiate alternator to maximum output.
68
If an ohmmeter reads 1 ohm between the rotor slip rings and the rotor shaft. What is indicated?
a. Readings is within specification.
b. Rotor coil windings are open.
c. Rotor coil windings are short to ground.
d. Rotor coil windings are shorted to each other
c. Rotor coil windings are shorted to
| ground.
69
A vehicle equipped with a remote starter will start with the key, but not with the remote device. Which of the following is a likely cause?
a. Defective ignition switch.
b. Burned ignition fusible link.
c. Inoperative starter solenoid.
d. Hood pin Switch shorted to ground
d. Hood pin Switch shorted to ground
70
A vehicle equipped with a road-speed sensitive, volume-controlled radio does not increase the volume as the road speed increases. Which of the following could be the likely cause?
a. Defective vehicle speed sensor.
b. Defective right front wheel speed sensor.
c. Open circuit between the vehicle speed sensor and the PCM.
d. Open circuit between PCM and radio
d. Open circuit between PCM and radio.
71
When replacing a non-deployed air-bag module, what should be done first?
a. Disconnect the diagnostic energy reserve module.
b. Disconnect the battery.
c. Disconnect the BCM.
d. Remove the trim screws
b. Disconnect the battery.
72
What instrument is commonly used to check the coil of an A/C compressor clutch?
a. Voltmeter.
b. Ohmmeter.
c. Ammeter.
d. Test lamp
b. Ohmmeter.
73
In an A/C system, where does the refrigerant change from high-pressure vapor to high-pressure liquid?
a. Orifice tube.
b. Accumulator.
c. Condenser.
d. Evaporator
c. Condenser.
74
When retrofitting a HFC-134a system in place of a R-12 A/C system, what must be changed?
a. Receiver-dryer.
b. Evaporator.
c. Compressor
d. Service fittings
d. service fittings
75
A sight glass used on a HFC-134a system, can be used to determine which of the following system problems?
a. An overcharged condition.
b. A complete loss of refrigerant.
c. Low system oil level.
d. An undercharged condition.
d. An undercharged condition.
76
A vacuum operated heater system, regardless of the control position, blows air out the floor vents all the times. Which of the following is the most likely cause?
a. Inoperative blend door.
b. Vacuum leak to the control head.
c. Binding heater door.
d. Binding motor door
c. Binding heater door.
77
A partially plugged A/C orifice tube will cause which of the following conditions?
a. Excessively low low-side pressure.
b. Excessively high low-side pressure.
c. Rapid cycling of the low-side pressure.
d. Compressor failure
c. Rapid cycling of the low-side pressure
78
What controls the flow of refrigerant into the evaporator in an Orifice tube system?
a. A thermostatic sensing device that controls the orifice size.
b. A throttling valve that controls the evaporator outflow.
c. A throttling valve that controls the evaporator inflow.
d. A pressure sensitive switch that turns the compressor clutch on and off.
d. A pressure sensitive switch that turns the compressor clutch on and off.
79
```
While checking an ABS diagnostic code, the left front wheel is identified as the source of the problem. During testing, AC voltage from the sensor is abnormally low. Which of the following could be the cause?
a. Shorted 5V reference signal wire.
b. Improper sensor air gap.
c. Defective EBCM (electronic brake
control module)
d. Open in sensor wires
```
b. Improper sensor air gap.
80
When installing an amplifier/subwoofer system in a vehicle with a 4-gauge power cable running from the battery positive terminal to the trunk, where is the ideal place for the fuse?
a. 12” (30cm) from the positive battery post.
b. At the firewall.
c. In the trunk, before the amplifier.
d. On the ground side
a. 12” (30cm) from the positive battery post.
81
If two 120w fog lamps are to be installed on a vehicle, assuming working voltage of 15V. What size of fuse should be used to properly protect the system?
a. 10 amps.
b. 15 amps.
c. 20 amps.
d. 25 amps
[ working current should not exceed 80% of fuse ratings]
c. 20 Amps. Using power eq: P = I x E
240 = 15 x E.
240/15 = E.
82
Which of the following should be used to perform an IOD (ignition-off draw) test on a vehicle?
a. Ohmmeter.
b. Ammeter.
c. Voltmeter.
d. Jumper wire
b. Ammeter
83
What colour is used for the high-voltage wiring insulation in high-potential hybrid vehicle electrician circuits?
a. Red.
b. Orange.
c. White.
d. Blue
b. Orange.
84
Which of the following electrical cable sizes would be an appropriate specification for an automobile battery cable?
a. AWG #2
b. AWG #6
c. AWG #10
d. AWG #14
a. AWG #2
85
Which of the following is the preferred method of testing the integrity of a series of standard blade-type fuses in an electrical fuse panel?
a. Pull each fuse, use DVOM ohmmeter to test continuity.
b. Pull each fuse, use jumper wires and an ammeter in series.
c. Use DVOM in V-DC mode and test each fuse in position at shoulder test points.
d. Pull each fuse and observe fusible medium through plastic
c. Use DVOM in V-DC mode and test each fuse in position at shoulder test points.
86
If an electrical accessory was spliced into part of the insulated circuit, which of the following would result in the circuit?
a. Current increase.
b. Current decrease.
c. Resistance increases.
d. Voltage decreases
a. more load is more current draw. Current increases.
87
When the conduit on a 12 V-DC insulated electrical wire wears through and it contact the vehicle’s frame, what results is known as?
a. An open
b. A fire.
c. A short to ground.
d. A short to voltage
c. short to ground.
88
You are performing an IOD test on an automobile equipped with multiple computer systems. The engine has been key-off for a 30-minute period and the ammeter reading 0.045Amps. What should you do next?
a. Remove all the fuses and retest.
b. One-by-one remove and replace each fuse and retest.
c. Nothing, 0.045 amps battery drain is acceptable.
d. Replace battery
c. Nothing, 0.045 amps battery drain is acceptable.
89
The electrical horn on a vehicle does not sound. Where should you begin to troubleshoot the malfunction?
a. At the horn.
b. At the horn circuit fuse.
c. At the horn button/switch.
d. At the horn relay
d. At the horn relay.
90
When a battery has to be disconnected from a vehicle, which of the following is the appropriate method for ensuring that no memory loss occurs in any of the vehicle computers networked to the data bus?
a. Quickly install a back-up battery after disconnecting the original.
b. Install a 9 V-DC battery anywhere in the circuit.
c. Plug a 12 V-DC memory saver into the power outlet/lighter socket.
d. Use booster cable from another vehicle to maintain chassis voltage.
c. a 12 V-DC memory saver into the power outlet/chassis lighter.
91
The high-voltage battery pack has become discharged on a hybrid-drive vehicle. What should be done to crank and start the engine?
a. The vehicle must be push started.
b. Boost from another vehicle with high-voltage hybrid drive.
c. The high-voltage battery pack must be slow-charged.
d. Boost using another 12 V-DC source to crank the secondary starter.
d. Boost using another 12 V-DC source to crank the secondary starter
92
Rotor resistance is being tested on an alternator by attaching DVOM leads to the A and F terminal screws. Which of the following must be done before performing the test?
a. Run the engine at 1500 rpm.
b. Remove the alternator from the engine.
c. Disconnect the battery.
d. Remove the alternator drive belt
c. Disconnect the battery.
93
A customer complains that the DRL (daytime running light) on his vehicle switch off when the engine is on and the parking brake actuated. Which of the following is the likely cause?
a. Short between the DRL and parking brake circuit.
b. Poor ground at DRL lamp socket.
c. Intermittent open in the DRL circuit.
d. Normal condition in some vehicles
d. : Normal condition in some vehicles
94
The turn signals on a vehicle equipped with dual filament tail-light bulbs flash rapidly when the right turn is signaled. Which of the following would be the more likely cause of this condition?
a. An open in the right-turn signal circuit.
b. A dead short to ground in the right-turn circuit.
c. Feedback connection at the bulb circuit between the turn and tail-light terminals.
d. Failed tail-light filament in the right-side dual filament bulb
Feedback connection at the bulb circuit between the turn and tail-light terminals
95
When an ohmmeter is connected with one lead to each of the slip rings and the resistance reading is below specs, the rotor is:
a. Shorted
b. Open
c. Grounded
d. OK
a. Shorted.
96
When an ohmmeter is connected with one lead to a slip ring and the other to the rotor shaft, a reading of 3 ohms would indicate the rotor is:
a. Open
b. Shorted
c. Grounded
d. OK
c. Grounded
97
With one ohmmeter lead connected to the stator lead and the other connected to the iron laminations, an infinite reading indicates that the stator is:
a. Open
b. Grounded
c. Shorted
d. OK
d. ok
98
By grounding the tab in the back of the Delco integral regulator alternator, we achieve maximum output by:
a. Grounding the sensing circuit
b. Grounding the field
c. Opening the field.
d. Grounding the stator
b. Grounding the field
99
A Delta wound stator can produce more current than a Y wound stator because the Delta windings are:
a. Longer
b. Heavier
c. In series
d. In parallel
d. In parallel
100
In many alternators, the diodes are assembled in a component called a (an):
a. Rectifier bridge
b. Regulator bridge
c. Diode housing
d. Insulator block
a. Rectifier bridge.
101
To bypass the voltage regulator in a "B" type charging system, the mechanic must:
a. Ground the field.
b. Isolate the field relay.
c. Supply 12 volts to the R terminal.
d. Supply 12 volts to the F terminal
d. Supply 12 volts to the F terminal
102
In an "A" circuit charging system, the voltage regulator is located between the:
a. Ignition switch and the field coil
b. Battery and the field coil
c. The field coil and the sensing circuit
d. The field coil and ground
d. The field coil and ground
103
In an alternator, output regulation is achieved by varying:
a. Field current.
b. Speed.
c. Stator current.
d. Magnetic polarity.
a. Field current.
104
The first step in inspecting the charging system is to:
a. Replace the alternator drive belt
b. Remove the alternator
c. Check the battery conditions
d. Check system voltage
c. Check the battery conditions
105
There should be battery voltage available at the alternator output terminal:
a. At all times
b. When the ignition is switched on
c. When the engine is running
d. If the regulator is defective
a. At all times.
106
Which of the following is NOT a typical alternator bench test?
a. Rotor continuity test
b. Stator ground test
c. Growler test
d. Diode test.
c. Growler test.
107
The magnetic field of an alternator is carried in the:
a. Stator
b. Rotor
c. Housing
d. Slip ring
b. Rotor
108
The output of an alternator is created in the:
a. Stator
b. Rotor
c. Housing
d. Brushes.
a. Stator
109
The indicator used to measure current flow into and out of the battery is the:
a. Voltmeter
b. Ammeter
c. Warning lamp
d. Field relay.
b. Ammeter
110
An alternator that makes a whining noise has a/an:
a. Shorted diode
b. Low output
c. Open stator
d. Open diode.
a. Shorted diode.
a. Shorted diode.
111
Which of the following would be the more likely cause of a HID lead-lamp failure?
a. Failed bulb filament.
b. Corroded bulb socket.
c. Failed HID control module.
d. Burned out electrodes.
d. Burned out electrodes
112
```
Which of the electrical devices supplies an input signal to the cruise-control electronics?
a. Instrument cluster unit.
b. Stoplight switch.
c. Tail-light bulb.
d. Turn light switch.
Ans: stop light switch
```
b. Stoplight switch
113
Source voltage on an automobile with its engine running and headlights switched on, is measured at 13.5V. If the voltage available at the positive terminal on one of the headlight is measured at 12.7V, which of the following is correct?
a. The charging circuit is defective.
b. The headlight circuit is functioning properly.
c. The headlight being tested is not properly grounded.
d. There is excessive resistance in the insulated side of the headlight circuit.
d. There is excessive resistance in the insulated side of the headlight circuit.
114
A headlight circuit uses a virtual, cycling circuit breaker. How does this differ from a headlamp circuit that uses a mechanical circuit breaker?
a. Virtual circuit breakers must be backed up-protected by a fuse.
b. Virtual circuit breakers can only handle low-current loads.
c. Virtual circuit breakers are more sensitive to voltage dump.
d. Virtual circuit breakers have no moving parts.
d. Virtual circuit breakers have no moving parts.
115
On a standard SAE-coded relay, what is the common terminal coded as?
a. 1.
b. 3.
c. 4
d. 5.
b. 3
116
How many wires are used in multiplexing backbone used by a CAN 2.0 data BUS(J1850) not counting the shield?
a. 16.
b. 8.
c. 2.
d. 1.
c. 2
117
When troubleshooting a complaint of insufficient passenger compartment heat during cold weather operation, which of the following possible causes should you check first?
a. Temperature of upper radiator hose.
b. Engine thermostat.
c. Heater core restriction.
d. Heater control valve operation. Ans: Temperature of upper radiator hose.
a. Temperature of upper radiator hose.
118
Which of the following would be the more costly consequence of using a mineral-base oil in a HFC-134a A/C system?
a. Reduce system performance.
b. Contaminated refrigerant.
c. Compressor failure due to insufficient lubrication.
d. Passenger compartment odor.
c. Compressor failure due to insufficient lubrication
119
What is the appropriate tool for electrically assessing the circuit for the field coils of an A/C compressor clutch?
a. Voltmeter.
b. Ammeter.
c. Diode tester.
d. Ohmmeter.
the system should be tested for Voltage using a voltmeter.
| a. voltmeter.
120
Under which of the following service procedures would it be acceptable to have both high and low side hand valves open at the same time?
a. Evacuating the A/C system.
b. Recharging with the A/C system running.
c. Checking for leaks with the A/C system running.
d. System performance testing with the A/C running
a. Evacuating the A/C system
121
What would result if a HFC-134a A/C system were 25% overcharged with refrigerant during servicing?
a. Passenger compartment temperature would be cooler than specified.
b. The A/C system would operate for 25% longer before service.
c. Ester oil becomes permanently contaminated.
d. The A/C system would operate at lower efficiency.
d. The A/C system would operate at lower efficiency.
122
What should prevent refrigerant discharge to atmosphere in the event os a high-pressure service valve leak in a HFC-134a system?
a. Depressor pin.
b. O-ring in the service valve cap.
c. Check engine alert to driver.
d. None, the refrigerant completely discharges to atmosphere
b. O-ring in the service valve cap.
123
What should prevent refrigerant discharge to atmosphere in the event of a high pressure service valve leak in an HFC-134a system?
a. depressor pin.
b. 0-ring in service valve cap.
c. check engine alert to driver.
d. none, the refrigerant completely discharges to
atmosphere.
b. 0-ring in service valve cap.
124
What would result if an HFC-134a A/C system were 25% overcharged with refrigerant during servicing?
a. passenger compartment would be cooler than
specified.
b. the A/C system would operate for 25% longer before
next service.
c. ester oil becomes permanently contaminated.
d. the A/C system would operate at lower efficiency.
d. the A/C system would operate at lower efficiency.
125
Under which of the following service procedures would it be acceptable to have both the high and low side hand valves open at the same time?
a. evacuating the A/C system.
b. recharging with the A/C system running.
c. checking for leaks with the A/C system running.
d. system performance testing with the A/C running.
a. evacuating the A/C system.
126
What is the appropriate tool for electrically assessing the circuit for the field coil of an A/C compressor clutch?
a. voltmeter.
b. ammeter.
c. diode tester.
d. ohmmeter.
d. ohmmeter.
127
Which of the following would be the more costly consequence of using a mineral base oil in an HFC 134a A/C system?
a. Reduce system performance.
b. Contaminated refrigerant.
c. compressor failure due to insufficient lubrication.
d. passenger compartment odour.
c. compressor failure due to insufficient lubrication.
128
What controls the flow of refrigerant into the evaporator in an orifice tube system?
a. a thermostatic sensing device that controls the
orifice size.
b. a throttling valve that controls the evaporator
outflow.
c. a throttling valve that controls the evaporator inflow.
d. a pressure sensitive switch that turns on the
compressor clutch on and off.
d. a pressure sensitive switch that turns on the
| compressor clutch on and off.
129
A partially plugged orifice tube will cause which if the following conditions?
a. excessively low low-side pressure.
b. excessively high low-side pressure.
c. rapid cycling of low-side pressure.
d. compressor failure
c. rapid cycling of low-side pressure.
130
A vacuum-operated heater system, regardless of the control position, blows air out the floor vents all the times. Which of the following is the most likely cause?
a. inoperative blend door.
b. vacuum leak to the control head.
c. binding heater door.
d. binding motor door.
c. binding heater door.
131
A sight glass used on an HFC 134a system can be used to determine which of the following system problem?
a. an overcharged condition.
b. a complete loss of refrigerant.
c. low system oil level
d. an undercharge condition.
d. an undercharge condition.
132
In an A/C system, where does refrigerant change from high pressure vapour to high pressure liquid?
a. orifice tube.
b. accumulator,.
c. condenser.
d. evaporator.
c. condenser.
133
What instrument is commonly used to check the coil of an A/C compressor clutch?
a. voltmeter.
b. ohmmeter
c. ammeter.
d. test lamp.
b. ohmmeter
134
Which of the following HVAC control door determines whether ventilation air flows through the heater core?
a. mode door.
b. defroster door.
c. blend door.
d. heater door
c. blend door.
135
Which of the following is a likely indication of low refrigerant charge in an HFC 134-a A/C system?
a. compressor damage.
b. higher than normal gauge readings.
c. noisy compressor operation.
d. faster than normal clutch cycling.
d. faster than normal clutch cycling.
136
```
What specific gravity reading taken at 20 degrees C would indicate that s lead acid battery was fully charged?
a. 1.100
b. 1.165.
c. 1.225
d 1.265
```
d. 1.265
137
After performing a hydrometer test on a fully charged battery, cell 1 has a specific gravity of 1.279 and cell 2 has a specific gravity of 1.225. What should be done with the battery?
a. recharge and test.
b. return to service.
c. replace
d. replace electrolyte.
c. replace
138
Which of the following electrical cable sizes would be an appropriate specification for an automobile battery cable?
a. AWG #2
b. AWG #6
c. AWG #10
d. AWG #14
a. AWG #2
American Wire Gauge cable sectional areas increases in size as the number specification lowers.
Electrical cable suitable for automotive battery cable are AWG numbers 0. 1. 2 and 4
139
When troubleshooting a complaint of insufficient passenger compartment heat, during cold weather operation, which of the following causes should be checked first?
a. temperature of upper radiator hose.
b. engine thermostat.
c. heater core restriction.
d. heater control valve operation
a. temperature of upper radiator hose.
140
How many wires are used in multiplexing backbone used by CAN 2.0 data bus (j1850), not counting the shield?
a. 16
b. 8
c. 2
d. 1
c. 2
two wires are used in the multiplexing backbone used by CAN 2.0 data bus (J1850)
The twisted pair may or may not be shielded
141
on a standard SAE-coded relay, what is the common terminal coded as?
a. 1
b. 3
c. 4
d. 5
b. 3
| the common terminal is coded #3
142
A headlight circuit used a virtual, cycling circuit breaker. How does this differ from a headlamp circuit that used a mechanical circuit breaker?
a. Virtual circuit breakers mush be back-up protected by
a fuse.
b. virtual circuit breakers can only handle low-current
loads.
c. virtual circuit breakers are more sensitive to voltage dump.
d. Virtual circuit breakers have no moving parts.
d. Virtual circuit breakers have no moving parts.
143
Which of the following would be the more likely cause of a HID headlamp failure?
a. failed bulb filament
b. corroded bulb socket.
c. failed HID control module.
d. burned out electrodes.
d. burned out electrodes.
144
Which of the electrical devices supplies an input signal to the cruise-control electronics?
a. instrument cluster unit.
b. stoplight switch.
c. tail light bulb.
d. turn light switch
b. stoplight switch.
145
The turn signals on a vehicle equipped with dual filament tail-light bulbs flash rapidly when a right turn is signaled. Which of the following would be the more likely cause of this condition?
a. an open in the right turn signal circuit
b. a dead short to ground in the right-turn circuit.
c. feedback connection at the bulb circuit between the
turn and tail light terminals.
c. feedback connection at the bulb circuit between the
turn and tail light terminals.
The increase flashing could be the result of higher current load through the flasher circuit. based on the responses provided, #c would be most suitable.
146
Rotor resistance is being tested on an alternator by attaching a DVOM leads to the A and F terminal screws. Which of the following must be done before performing the test?
a. run engine at 1500 rpm.
b. remove alternator from engine.
c. disconnect the battery.
d. remove alternator drive belt.
c. disconnect the battery.
147
The high-voltage battery pack has become discharged on a hybrid-drive vehicle. What should be done to crank and start the engine?
a. the vehicle mush be push started.
b. Boost from another vehicle with high-voltage hybrid
drive.
c. the high voltage battery pack must be slow-charged.
d. Boost using another 12v-DC source to crank the
secondary starter.
d. Boost using another 12v-DC source to crank the
| secondary starter.
148
You are performing an IOD test on an automobile equipped with multiple computer systems. The engine has been key-off for a 30-minute period and the ammeter reading is 0.045 amps. What should you doo next?
a. remove all the fuses and retest.
b. one-by-one , remove and replace each fuse and
retest.
c. nothing. 0.045 amps battery drain is acceptable.
d. replace the battery.
c. nothing. 0.045 amps battery drain is acceptable.
149
Which of the following is the preferred method of testing the integrity of a series of standard blade type fuses in an electrical fuse panel?
a. pull each fuse , use a DVOM ohmmeter to test
continuity.
b. pull each fuse, use jumper wires and ammeter in
series.
c. use DVOM in v-dc mode and test each fuse in
position at shoulder test.
d. pull each fuse and observe fusible medium through
the plastic.
c. use DVOM in v-dc mode and test each fuse in
| position at shoulder test.
150
Which of the following should be used to perform an IOD ( ignition-off draw) test on a vehicle?
a. Ohmmeter
b. Ammeter
c. voltmeter.
d. Jumper wire
b. Ammeter
151
if two 120w fog lamps are to be installed on a vehicle, assuming working voltage of 15V, what size fuse should be to properly protect the system?
a. 10 amps
b. 15 amps.
c. 20 amps.
d. 25 amps
c. 20 amps.
```
P=I x R
[ 2 x 120] = 15 x E
240/15 = E
E =16
rule of thumb circuit current should be at least 80% of protection ratings
16 amps if 80% of 20
```
152
Which of the following is an acceptable maximum
AC voltage leakage output from an alternator in a normal load condition.
a. 0.5 to 1.0 V-AC
b. 0.1 to 0.5 V-AC
c. 1.0 to 1.5 V-AC
d. 13.5 to 15.5 V-AC
b. 0.1 to 0.5 V-AC
153
Which of the following would cause a starter motor to whine while engaged?
a. defective solenoid.
b. worn nose cone roller-bearing set.
c. defective flywheel ring gear.
d. worn starter brushes
c. defective flywheel ring gear.
154
Which of the following could cause excessive alternator whine?
a. no load operation.
b. defective diodes.
c. defective rear bearings.
d. glazed belt.
b. defective diodes.
155
When cranking an engine the starter motor turns over slowly. Which of the following is a probable cause?
a. Neutral safety switch.
b. Worn starter bushings.
c. Ignition switch high resistance.
d. starter mounting for flange corrosion
d. starter mounting for flange corrosion
156
Which of the following tests would be most effective in identifying the location of high resistance in a starting circuit?
a. resistance test with an ohmmeter.
b. current draw test with an ammeter.
c. voltage drop test with a voltmeter.
d. check OBD II fault codes.
c. voltage drop test with a voltmeter
157
When checking starter current draw with an inductive ammeter clamp, which of the following should be done?
a. disconnect the battery ground terminal.
b. disconnect the alternator.
c. crank the engine.
d. run the engine at idle speed
c. crank the engine.
158
What would be likely result of a poorly grounded voltage regulator?
a. discharged battery.
b. burnt out alternator.
c. arching noise in alternator
d. excessively high charging voltage
d. excessively high charging voltage
159
What is the maximum voltage drop for any given wire of connection on an alternator?
a. 0.2 V-DC
b. 0.5 V-DC
c. 1.0 V-DC
d. 1.5 V-DC
a. 0.2 V-DC
160
which of the following is being done to an alternator when battery voltage is applied directly to the field terminals?
a. shorting
b. full-loading
c. full-fielding
d. zero-loading
c. full-fielding
161
when setting up to test the amperage output of an alternator, where should the clamps of a carbon pile tester be located?
a. battery positive and battery negative.
b. alternator B+ and ground.
c. alternator B+ and alternator F terminal
d. starter motor positive and alternator B+
a. battery positive and battery negative.
162
Where should the leads of a DVOM be placed to check for excessive current drain using an ohmmeter on a vehicle battery?
a. Disconnect battery-ground and check between it
and chassis.
b. disconnect battery-positive cable and check
between it and chassis.
c. suspected current drain cannot be checked with an
ohmmeter
d. disconnect alternator BAT+ and check between it
and chassis
b. disconnect battery-positive cable and check
| between it and chassis.
