Electrical and Comfort Control Systems

Question 0

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.

Answer 0

c. The engine is seized or is mechanically locked.

Question 1

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.

Answer 1

a. Check voltage drops in the circuit, then check for current draw.

Question 2

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.

Answer 2

b. Fuel pump relay contacts are stuck closed.

Question 3

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

Answer 3

d. A faulty hazard flasher

Question 4

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

Answer 4

c. Window switch

Question 5

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.

Answer 5

a. Measure the current flow in the brake circuit to each wheel to verify the connections are secure.

Question 6

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 hight, 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.

Answer 6

c. When a balancing coil gauge indicates a high reading, the sending unit will have high resistance.

Question 7

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.

Answer 7

b. The positive cable should be connected to the charged battery first?

Question 8

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.

Answer 8

b. Perform a battery test, then test starter draw.

Question 9

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.

Answer 9

b. Solder the wires, then position the tubing and apply heat.

Question 10

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.

Answer 10

b. Install a static strap, then remove the cluster from the anti-static bag.

Question 11

A tech check 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

Answer 11

b. Temperature blend control door malfunction

Question 12

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

Answer 12

c. Plugged evaporator

Question 13

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”

Answer 13

d. The refrigerant is a contaminated “cocktail”

Question 14

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

Answer 14

d. Temperature blend door malfunction

Question 15

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

Answer 15

c. 107C

Question 16

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.

Answer 16

c. Remove the air box, then sanitize the evaporator.

Question 17

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.

Answer 17

a. A/C systems are evacuated to remove moisture and air from the system.

Question 18

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.

Answer 18

b. Drain and flush the system, then add new coolant.