Question 1

Marker lamps are located on the sides of the truck or trailer.

Accepted Answer

Marker lamps are used to indicate the width and length of a vehicle, and they are typically placed on the sides of trucks or trailers to enhance visibility and safety.

Question 2

The center pin of a green-colored SAE J560 7-way trailer receptacle is the trailer ABS power supply.

Accepted Answer

The center pin of a green-colored SAE J560 7-way trailer receptacle is the trailer ABS power supply.

Question 3

Referring to the figure shown below, a disconnected turn signal switch electrical connector would prevent the park lamps from illuminating with the park light switch closed.

Accepted Answer

False

Question 4

Referring to the figure shown below, a burned out left rear turn signal lamp filament could cause the left front turn signal to not illuminate at all with the turn signal switch in the left turn position.

Accepted Answer

The answer of Referring to the figure shown below, a...

Question 5

Referring to the following figure, an internal short circuit between the right rear lamp filaments may cause the front lamps to illuminate when the stop light switch is closed even though the park light switch is open.

Accepted Answer

The answer of Referring to the following figure, an internal...

Question 6

The clearance lamps are the three lamps at the highest point of the tractor or trailer.

Accepted Answer

Clearance lamps are located at the outermost edges of the vehicle to indicate its width and height, not necessarily three lamps at the highest point.

Question 7

LED lamps draw considerably more current than an equivalent incandescent lamp.

Accepted Answer

LED lamps are more energy-efficient and draw less current than equivalent incandescent lamps for the same light output.

Question 8

The trailer lighting is typically designed to be grounded through the fifth-wheel.

Accepted Answer

Trailer lighting is typically grounded through the trailer's own electrical system, not through the fifth-wheel, which is a coupling device for connecting a trailer to a truck.

Question 9

Air brake stop lamp switches are typically normally-closed mechanically-actuated switches that detect the movement of the foot valve.

Accepted Answer

Air brake stop lamp switches are typically normally-open switches that close when the brake pedal is pressed, allowing current to flow and activate the stop lamps.

Question 10

The hazard lamps (four-ways) always have priority over the stop lamps (hazard lamps override the stop lamps).

Accepted Answer

Hazard lamps and stop lamps are separate systems; activating hazard lamps does not override or disable stop lamps.

Question 11

One low-beam headlamp has burned out on a truck. What is the reason that the other low-beam headlamp is unaffected?
A) The low-beam headlamps are wired in series.
B) The low-beam headlamps are wired in parallel.
C) The high-beam filament provides an alternate path for current resulting in a backfeed.
D) Kirchhoff's current law

Accepted Answer

The low-beam headlamps are wired in parallel, so if one burns out, the other remains unaffected because each lamp has its own separate circuit path.

Question 12

Technician A says that an open ground circuit for a dual-filament lamp always causes the lamp to not illuminate. Technician B says that amber-colored stop lamp lenses should be used at the rear of the truck if the truck has separate stop/turn lamps. Who is correct?
A) A only
B) B only
C) Both A and B
D) Neither A nor B

Accepted Answer

An open ground circuit can cause a dual-filament lamp to not illuminate, but it is not always the case as it depends on the circuit configuration. Amber-colored lenses are typically used for turn signals, not stop lamps, which are usually red.

Question 13

Referring to the figure shown below, which failure could cause the right rear stop lamp to not illuminate with the stop light switch closed yet all other lamps still illuminate correctly?

A) Defective stop light switch
B) Shorted to ground circuit between terminal 3 of the turn signal switch and the right rear lamp
C) Open ground for the right rear lamp
D) Open circuit between terminal 3 of the turn signal switch and the right rear lamp

Accepted Answer

The answer of Referring to the figure shown below, which...

Question 14

Referring to the following figure, technician A says that a shorted to ground circuit between the park light switch and the right front park lamp would likely cause all park lamps shown to not illuminate. Technician B says that if the fuses supplying the stop light switch and the turn signal flasher are both blown, this most likely indicates a short to ground between terminal 4 and the left front lamp or between terminal 6 and the right front lamp. Who is correct?

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

Accepted Answer

The answer of Referring to the following figure, technician A...

Question 15

The reason for incandescent lamp surge current when initially switched on is attributed to__________.
A) Lenz's law
B) CEMF
C) the positive temperature coefficient of tungsten
D) the negative temperature coefficient of tungsten

Accepted Answer

The positive temperature coefficient of tungsten means that its resistance increases with temperature. When the lamp is first switched on, the filament is cold and has low resistance, leading to a surge in current. As it heats up, the resistance increases, reducing the current.

Question 16

Technician A says that adding additional marker lamps to a trailer requires a larger circuit breaker to be installed in the tractor to adequately protect the existing wiring. Technician B says that it is always best to connect the black and brown colored trailer wires together so that a short to ground in the trailer wiring will still permit some of the trailer running lamps to illuminate. Who is correct?
A) A only
B) B only
C) Both A and B
D) Neither A nor B

Accepted Answer

Adding additional marker lamps requires ensuring the circuit can handle the extra load, but it doesn't necessarily mean a larger circuit breaker is needed; it could require rewiring or using a relay. Connecting black and brown wires together is incorrect as it can cause electrical issues or shorts.

Question 17

Which of the following is a true statement?
A) It is ok to touch a halogen lamp bulb provided you have clean hands.
B) Front turn signals may be red in color in North America.
C) Back up lamps are required on all trailers in North America.
D) Conspicuity refers to reflective material.

Accepted Answer

Conspicuity refers to the use of reflective materials or lights to make objects more visible, especially in low-light conditions.

Question 18

Technician A says that instrument panel illumination may be controlled by a rheostat. Technician B says that instrument panel illumination may be controlled by pulse width modulation. Who is correct?
A) A only
B) B only
C) Both A and B
D) Neither A nor B

Accepted Answer

Both Technician A and Technician B are correct. Instrument panel illumination can be controlled by a rheostat, which adjusts resistance to change brightness, and by pulse width modulation, which adjusts the duty cycle of the power signal to control brightness.

Question 19

The dome lamps will not switch off when both doors are closed on a truck. Which of the following could be the cause?
A) Shorted to ground circuit between the dome lamp and the door switches
B) Left side door switch is remaining closed with door closed
C) Right side door switch is remaining closed with door closed
D) All of the above could cause this problem.

Accepted Answer

All of the above could cause the dome lamps to remain on. A short to ground could bypass the switch, and either door switch remaining closed would indicate to the system that a door is still open.

Question 20

The headlamps and other incandescent lamps have a history of burning out repeatedly on a truck a short time after being replaced. Which of the following could be the cause?
A) Poor fifth wheel ground
B) Batteries with too high of a CCA have been installed
C) Low charging system voltage
D) High charging system voltage

Accepted Answer

High charging system voltage can cause the headlamps and other incandescent lamps to burn out quickly due to excessive voltage leading to overheating and failure of the bulbs.

Quiz 9: Lighting Systems

Marker lamps are located on the sides of the truck or trailer.

The center pin of a green-colored SAE J560 7-way trailer receptacle is the trailer ABS power supply.

Referring to the figure shown below, a disconnected turn signal switch electrical connector would prevent the park lamps from illuminating with the park light switch closed.

Referring to the figure shown below, a burned out left rear turn signal lamp filament could cause the left front turn signal to not illuminate at all with the turn signal switch in the left turn position.

Referring to the following figure, an internal short circuit between the right rear lamp filaments may cause the front lamps to illuminate when the stop light switch is closed even though the park light switch is open.

The clearance lamps are the three lamps at the highest point of the tractor or trailer.

LED lamps draw considerably more current than an equivalent incandescent lamp.

The trailer lighting is typically designed to be grounded through the fifth-wheel.

Air brake stop lamp switches are typically normally-closed mechanically-actuated switches that detect the movement of the foot valve.

The hazard lamps (four-ways) always have priority over the stop lamps (hazard lamps override the stop lamps).

One low-beam headlamp has burned out on a truck. What is the reason that the other low-beam headlamp is unaffected?

Technician A says that an open ground circuit for a dual-filament lamp always causes the lamp to not illuminate. Technician B says that amber-colored stop lamp lenses should be used at the rear of the truck if the truck has separate stop/turn lamps. Who is correct?

Referring to the figure shown below, which failure could cause the right rear stop lamp to not illuminate with the stop light switch closed yet all other lamps still illuminate correctly?

The reason for incandescent lamp surge current when initially switched on is attributed to__________.

Which of the following is a true statement?

Technician A says that instrument panel illumination may be controlled by a rheostat. Technician B says that instrument panel illumination may be controlled by pulse width modulation. Who is correct?

The dome lamps will not switch off when both doors are closed on a truck. Which of the following could be the cause?

The headlamps and other incandescent lamps have a history of burning out repeatedly on a truck a short time after being replaced. Which of the following could be the cause?