Deck 10: Electrical Accessories

Question 1

Referring to figure shown below, an open circuit 90H supplying the high side of the Hyd Brake Relay (300) would cause the pump motor to not operate.

Answer 1

True

Question 2

Referring to the following figure, assuming fuse F9 is supplied with unswitched battery positive voltage, closing the Stop Light Switch (51) will cause the T/S relay (660) to be energized.

Answer 2

True

Question 3

Referring to the figure shown below, a short to ground of circuit 11-GZ would prevent likely blow both fuses F5-A and F8-C.

Answer 3

False

Question 4

Referring to the following figure, assuming that fuse F8-C should be supplied with 12V when the park lamps are on, if neither mirror lamp illuminates with the headlamp switch in the ON position then this could be an indication to the operator that he does not have any trailer tail lamps.

Question 5

Referring to following figure, the heated mirror switch contains incandescent lamps for panel illumination and ON indicator.

Question 6

The wiper motor typically reverses its direction of rotation to cause the windshield wipers to move back and forth across the windshield.

Question 7

A two-speed wiper motor would typically have three brushes.

Question 8

Intake manifold vacuum is used to control the mode and temperature doors for the HVAC system on most trucks with diesel engines.

Question 9

Referring to the figure shown below, a short to ground of circuit A77C would most likely cause fuse F15 to blow.

Question 10

Referring to the following figure, the A/C compressor would not be energized with the Mode Switch in the A/C position and the blower switch in the OFF position.

Question 11

An A/C clutch coil is being tested. Why is it important to observe the correct polarity of voltage supplied to the coil?

A) A series-connected diode permits current to flow through the coil in only one direction.
B) A parallel-connected suppression diode can be destroyed.
C) The direction that the coil is wound requires current flow in only one direction.
D) All of the above.

Question 12

Referring to the figure shown below, technician A says that a shorted to ground circuit 90L between the differential pressure switch and the flow switch will cause the pump motor to run even though both the differential pressure and flow switches are open. Assuming fuse F33 is supplied with unswitched battery positive voltage and that the flow switch is normally closed, technician B says that closing the hydraulic brake switch (50) with ignition off should cause the pump motor to operate. Who is correct?

A) A only
B) B only
C) Both A and B
D) Neither A nor B

Question 13

Referring to the figure shown below, assuming fuse F3 is supplied with ignition voltage, which failure(s) could cause the pump motor to run at all times even with ignition switch in the OFF position?

A) Defective flow switch
B) Defective pressure differential switch
C) Misadjusted hydraulic brake switch
D) All of the above could cause this failure.

Question 14

Referring to the following figure, technician A says that a blown fuse F8-C would prevent both heated mirrors from operating. Technician B says that a blown fuse F5-A would prevent both mirror lights from illuminating. Who is correct?

A) A only
B) B only
C) Both A and B
D) Neither A nor B

Question 15

Referring to the figure shown below, which failure(s) could cause both mirror lights to illuminate when the mirror heat switch is in the ON position even though the park lamps are switched OFF?

A) Wire-to-wire short between circuits 78B and 58J
B) Wire-to-wire short between circuits 78A and 58B
C) Open of circuit 11-GZ
D) All of the above could cause this failure.

Question 16

Technician A says that a broken clockspring could cause airbag deployment. Technician B says that an inoperative electric horn could be caused by a broken clockspring. Who is correct?

A) A only
B) B only
C) Both A and B
D) Neither A nor B

Question 17

Which of the following is a true statement?

A) A low pressure A/C cutout switch may prevent A/C compressor operation in extreme cold ambient temperatures.
B) A low pressure A/C cutout switch may prevent A/C compressor operation if there is insufficient refrigerant in the system.
C) A high pressure A/C cutout switch may prevent A/C compressor operation if the air flow through the condenser is restricted.
D) All of the above are true statements.

Question 18

Technician A says that air should flow though a normally-closed air solenoid when the solenoid is not energized. Technician B says that there should be continuity between the common terminal and normally-closed terminal of a relay that is not energized. Who is correct?

A) A only
B) B only
C) Both A and B
D) Neither A nor B

Question 19

Referring to the following figure, the blower motor does not operate in High speed but operates correctly in Low or Med speeds. What could be the cause?

A) Defective resistor block
B) Shorted to ground circuit A77F
C) Defective blower switch
D) All of the above could cause this problem.

Question 20

Referring to the following figure, a work order indicates no A/C cooling. The blower motor is found to operate correctly. Which of the following could be the cause?

A) Blown fuse F12
B) Low A/C refrigerant level (low pressure in system)
C) Open circuit A77-GB
D) Both B and C