Lighting Systems: Other Hummer H2 I

Intermittent

Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Backup Lamps Always On

Backup Lamps Always On

Backup Lamps Inoperative

Backup Lamps Inoperative

Clearance Lamps Inoperative

Clearance Lamps Inoperative

Courtesy Lamps Always On

Courtesy Lamps Always On

Courtesy Lamps Inoperative

Courtesy Lamps Inoperative

Daytime Running Lamps (DRL) Always On

Daytime Running Lamps (DRL) Always On

Daytime Running Lamps (DRL) Inoperative

Daytime Running Lamps (DRL) Inoperative

Hazard Lamps Always On

Hazard Lamps Always On

Hazard Lamps Inoperative

Hazard Lamps Inoperative

Headlamps Always On - Low or High Beam

Headlamps Always On - Low or High Beam

Headlamps Inoperative - High Beams

Headlamps Inoperative - High Beams

Headlamps Inoperative - Low Beams

Headlamps Inoperative - Low Beams

Headlamps Inoperative - Low and High Beams (All)

Headlamps Inoperative - Low and High Beams (All)

Headlamps Inoperative - Low and High Beams (With Front Wipers On)

Headlamps Inoperative - Low and High Beams (With Front Wipers On)

Headlamps Inoperative - Flash to Pass

Headlamps Inoperative - Flash to Pass

High Beam Indicator Always On

High Beam Indicator Always On

High Beam Indicator Inoperative

High Beam Indicator Inoperative

Interior Backlighting Does Not Dim

Interior Backlighting Does Not Dim

Interior Backlighting Inoperative

Interior Backlighting Inoperative

Instrument Panel (I/P) Compartment Lamp Inoperative

Instrument Panel (I/P) Compartment Lamp Inoperative

Instrument Panel (I/P) Compartment Lamp Always On

Instrument Panel (I/P) Compartment Lamp Always On

Off-Road Lamps Always On

Off-Road Lamps Always On

Off-Road Lamps Inoperative

Off-Road Lamps Inoperative

Park, License, and Tail Lamps Always On

Park, License, and Tail Lamps Always On

Park, License, and Tail Lamps Inoperative

Park, License, and Tail Lamps Inoperative

Reading Lamp(s) Inoperative

Reading Lamp(s) Inoperative

Stop Lamps Always On

Stop Lamps Always On

Stop Lamps Inoperative

Stop Lamps Inoperative

Turn Signal Lamps and/or Indicators Always On or Flashing

Turn Signal Lamps and/or Indicators Always On or Flashing

Turn Signal Lamps and/or Indicators Inoperative

Turn Signal Lamps and/or Indicators Inoperative

Vanity Mirror Lamp(s) Inoperative

Vanity Mirror Lamp(s) Inoperative

Tools Required

J 25300-D Headlamp Aimer. See Special Tools and Equipment .

The screen method is preferred for aiming headlamps. If the headlamp is equipped with aiming pads, headlamp aiming may be performed using the alternate procedure.

Headlamp aiming is done with the low beam lamps. The high beam lamps will be correctly aimed if the low beam lamps are aimed properly. If the high beam needs adjustment, follow the screen method using the high beam bulb as the reference for measurements.

Screen Method for Headlamp Aiming (Visual Aim)

The screen method requires an area set up specifically for headlamp aim.

Scheme 30

The area should consist of a level surface large enough to allow for a vehicle and an additional 7.62 m (25 ft) as measured from the face of the headlamps to the aiming screen.

The screen should be a wall or other flat surface at least 1.52 m (5 ft) high by 3.66 m (12 ft) wide with a matte white surface well shaded from extraneous light, and 90 degrees to the floor. The screen should be provided with a permanent vertical reference line 0.61 m (2 ft) from the left edge of the screen, 2 laterally adjustable vertical tapes, and one vertically adjustable horizontal tape.

After the aiming screen has been set up and located, paint or tape a reference line on the floor 15.24 m (50 ft) from the vertical reference line on the screen. This line should be perpendicular to the aiming screen and a mark placed at 7.62 m (25 ft) from the screen.

Headlamp Aiming Procedure

1. Align the left tires of the vehicle with the reference line extending from the screen with the headlamps aligned with the reference line.
2. Remove any snow, ice or mud from the vehicle.
3. The vehicle should be fully assembled and all other work stopped while the headlamp aiming is being done.
4. The vehicle should contain cargo or be loaded to represent normal vehicle use.
5. Tires should be properly inflated.
6. Rock the vehicle to stabilize the suspension.
7. Measure from the floor to the center of the lamp bulb on the vehicle. Some lamps have an aim dot marked on the lens.
8. At the screen, measure from the floor and place the horizontal tape at the measured distance.
9. Measure from the reference line on the floor to the left headlamp bulb centerline.
10. At the screen, measure from the reference line and place the vertical tape at the measured distance.
11. Measure from the reference line on the floor to the right headlamp bulb centerline.
12. At the screen, measure from the reference line and place the vertical tape at the measured distance.
13. Turn the headlamps ON.
14. Adjust the headlamps to the specifications required by state and local authorities.

Alternate Aiming Procedure

Instructions for use accompany the tool.

This procedure may only be used on headlamps equipped with aiming pads. Adjustment settings are embossed on the headlamp lens. They are typically located near the aiming pads. In some cases, the adjustment settings are located in other areas of the lens. They will be represented by a number followed by the letter "V" or the letter "H".

1. Remove any snow, ice or mud from the vehicle.
2. The vehicle should be fully assembled and all other work stopped while the headlamp aiming is being done.
3. The vehicle should contain cargo or be loaded to represent normal vehicle use.
4. Tires should be properly inflated.
5. Rock the vehicle to stabilize the suspension.
6. Using the J 25300-D , adjust the headlamps to the specifications required by state and local authorities. See «Special Tools and Equipment»(ref-187211-S05603111222005083100000) .

Exterior Lamps

The exterior lighting system consists of the following lamps

1. The headlamps
2. The daytime running lamps (DRL)
3. The park, tail and marker lamps
4. The turn signal lamps
5. The stop lamps
6. The backup lamps
7. The clearance lamps
8. The off-road lamps

Headlamps

With automatic lamp control (ALC) the headlamps may be turned on in 3 different ways. Some export vehicles are not equipped with ALC, disabling the ALC, DRL, and wiper activated headlamp (WAH) functions in the module. With ALC disabled, the headlamps will operate in the manual mode. In these vehicle diagnostics the term AUTO shall be equivalent to OFF when referencing headlamp switch positions. First, when the driver places the headlamp switch in the ON position, for normal operation. Second, with the headlamp switch placed in the AUTO position, for ALC. During ALC, the headlamps will be in daytime running lamp (DRL) operation in daylight conditions, or headlamp operation in low light conditions. Third, in WAH mode. Only when the wiper system is activated while the vehicle is in gear, the wiper blades have completed at least 3 cycles, and a 35 second time period expires, will the body control module (BCM) switch from DRL mode to headlamp mode during daylight conditions. When the gearshift lever is placed in the PARK or NEUTRAL position or if the wipers are turned off, normal manual, or ALC operation will resume after approximately 60 seconds

Headlamp ON/OFF control is determined by the BCM by a signal on the headlamp switch on input circuit when the headlamp switch is in the ON position. When the headlamp switch is in the AUTO position, the BCM determines headlamps ON/OFF by the voltage from the ambient light sensor.

The BCM will also illuminate the headlamps and park lamps after the front wipers have been turned ON. The windshield wiper module signals the BCM on the windshield wiper switch signal 2 circuit when the windshield wipers are ON.

The high beam headlamps receive voltage from the headlamp high relay located in the underhood fuse block. The BCM controls the relay on the headlamp high beam relay control circuit. High beam control is determined by a signal on the headlamp dimmer switch signal circuit from the multifunction switch. When the headlamp dimmer switch signal circuit is grounded, the BCM grounds the headlamp high beam relay control circuit, illuminating the high beam headlamps. The right and left high beam circuits are independent and are fused independently in the underhood fuse block. The right and left headlamps are grounded at G100 and G104.

The low beam headlamps receive voltage from the headlamp low relay located in the underhood fuse block. The BCM controls the relay on the headlamp low beam relay control circuit. Low beam control is determined by a signal on the headlamp dimmer switch signal circuit from the multifunction switch. When the headlamp dimmer switch signal circuit is open, the BCM grounds the headlamp low beam relay control circuit, illuminating the low beam headlamps. The right and left low beam circuits are independent and are fused independently in the underhood fuse block. The right and left headlamps are grounded at G100 and G104.

If the headlight switch is left in the ON position, the inadvertent power control feature will turn off the headlamps approximately 10 minutes after the ignition switch is turned to the OFF position. If the driver places the headlamp switch in the ON position after the ignition switch has been turned OFF, or if the ignition switch is in the ACCY position, the headlamps will remain on until turned off, or the battery runs dead.

The high beam indicator is illuminated when the instrument cluster receives a class 2 serial data message from the BCM that the high beams are illuminated.

Daytime Running Lamps (DRL)

The daytime running lamps (DRL) will operate when the ignition switch is in the RUN position, the gear selector is not in the PARK position, and the headlamp switch is in the AUTO position. When these conditions have been met and the ambient light sensor indicates daytime conditions, the DRL will illuminate. Some export vehicles are not equipped with automatic lamp control (ALC), disabling the ALC, DRL and wiper activated headlamp (WAH) functions in the module. With ALC disabled, the headlamps will operate in the manual mode. In these vehicle diagnostics, the term AUTO shall be equivalent to OFF when referencing headlamp switch positions.

The ambient light sensor is a light sensitive transistor that varies its voltage signal to the body control module (BCM) in response to changes to the outside (ambient) light level. When the BCM receives this signal it will either turn on the DRL or the headlamps for auto headlamp operation. Any function or condition that turns on the headlamps will cancel the DRL operation. The DRL can be manually turned OFF by depressing the AHL/DRL defeat switch in the headlamp switch. The AHL/DRL defeat switch sends a ground signal through the DRL switch signal circuit to the BCM. The BCM then turns OFF the DRL. When the AHL/DRL are manually turned OFF at the headlamp switch, the AHL/DRL will default to ON with the next ignition cycle. The DRL are separate lamps independent of the headlamps. With the headlamp switch in the AUTO position, the DRL will either be turned ON or OFF, after an approximate 8 second delay depending on whether daylight or low light conditions are sensed. The DRL 10 A fuse in the underhood fuse block supplies battery positive voltage to the DRL relay switch contacts and relay coil. When the BCM energizes the DRL relay on the DRL relay control circuit in daylight conditions, the DRL receives voltage on the DRL supply voltage circuit. Ground for the DRL is at G100.

Park, Tail and Marker Lamps

The park, tail, and marker lamps, including the license lamps, are turned on when the headlamp switch is placed in the PARK or ON position, or anytime the headlamps are requested. The underhood fuse block supplies battery positive voltage to both the park lamp relay switch contacts and the park lamp coil circuit. The body control module (BCM) provides a ground or control circuit to the park lamp relay coil circuit. When the park lamps are turned on the BCM energizes the park lamp relay. Current flow is from the park lamp relay to the FR PRK 10 A fuse, RR PRK 10 A fuse, LR PRK 10 A fuse, and the TRL PRK 10 A fuse, and to their respective park and marker lamps. The front park and marker lamps are grounded at G100. The rear park and marker lamps are grounded at G401. The license lamps are grounded at G410. If the headlamp switch is left in the ON position, the inadvertent power control feature will turn off the park, tail, and marker lamps, approximately 10 minutes after the ignition switch is turned to the OFF position. If the driver places the headlamp switch in the ON position after the ignition switch has been turned OFF, or if the ignition switch is in the ACCY position, the park, tail and marker lamps will remain on until turned off or the battery runs dead.

Turn Signal Lamps

The IGN E 10 A fuse in the underhood fuse block supplies battery positive voltage to the turn signal/hazard switch assembly. The FLASH 25 A fuse in the I/P fuse block supplies battery positive voltage to the turn signal/flasher module and ground is supplied at G200. When the turn signal switch is placed in either the left or right position, the circuit is complete from the turn signal switch to the turn sign/flasher module. The turn sign/flasher module then sends an on-off voltage signal through the LT TRLR, RT TRLR, LT TURN or RT TURN FUSES in the I/P fuse block to the appropriate turn signal. The instrument panel cluster (IPC) indicators also receive voltage from the LT TURN and RT TURN fuses. The audio chime is also activated when the turn signals are on. When the hazard switch is pressed, all turn signal lamps will flash including both IPC turn indicators. The front turn signals are grounded at G100. The rear turn signals are grounded at G401.

Stop Lamps

The STOP LP 25 A fuse in the underhood fuse block supplies battery positive voltage to the normally open stop lamp switch. When the driver presses the brake pedal, the switch contacts close and battery positive voltage is supplied to both the STOP 15 A fuse and the CHMSL 10 A fuse in the IP fuse block, and to the turn signal switch. The turn signal/hazard module then supplies voltage to both of the trailer rear turn/stop lamp supply voltage circuits. The voltage from the CHMSL 10 A fuse is to the center high mounted stop lamp (CHMSL) and the trailer jumper harness. The voltage from the STOP 15 A fuse is to the stop lamps, throttle actuator control (TAC) module, and the electronic brake control module (EBCM). The CHMSL is grounded at G410. The stop lamps are grounded at G401.

Backup Lamps

The backup lamp request signal is sent from the powertrain control module (PCM) to the body control module (BCM) on the class 2 message system. This signal is based on the park neutral position (PNP) switch signal. The BCM supplies voltage on the backup lamp supply voltage circuit to the backup lamps and to the automatic day/night mirror. Voltage for the courtesy lamp supply voltage circuit and backup lamp supply voltage circuit is from the TBC B fuse in the instrument panel fuse block directly through the BCM to these circuits. A short to ground on either of these circuits will open the fuse. The backup lamps are grounded at G401.

For trailer wiring, a separate backup lamp circuit is connected through the underhood fuse block from the TRLR B/U 10 A fuse to the trailer wiring harness.

Clearance Lamps

The clearance lamps, are turned on when the headlamp switch is placed in the PARK or ON position or anytime the headlamps are requested. The underhood fuse block supplies battery positive voltage to both the park lamp relay switch contacts and the park lamp coil circuit. The body control module (BCM) provides a ground or control circuit to the park lamp relay coil circuit. When the park lamps are turned on the BCM energizes the park lamp relay. Current flow is from the park lamp relay to the INT PRK 10 A fuse, and to the clearance and roof lamps. The front clearance and roof lamps are grounded at G203. The rear clearance and roof lamps are grounded at G410. If the headlamp switch is left in the ON position, the inadvertent power control feature will turn off the park, tail, and clearance lamps, approximately 10 minutes after the ignition switch is turned to the OFF position. If the driver places the headlamp switch in the ON position after the ignition switch has been turned OFF, or if the ignition switch is in the ACCY position, the park, tail, and marker lamps, will remain on until turned off or the battery runs dead.

Off-Road Lamps

The off-road lamps are available in several configurations with lights mounted on the roof and on the front brush guard. The lamps are controlled by a single, rocker type switch, located on the overhead console. When the switch is closed, voltage is supplied to the relays on the off-road lamps relay control circuit. When the relays are energized, voltage is on the front, roof 1, and roof 2 off-road lamps supply voltage circuits, depending on the configuration of lamps.

Interior Lamps

The interior lighting consist of the following 2 groups. This first group includes lamps that may not be dimmed.

1. The courtesy/Illuminated entry lamps
2. The dome lamps
3. The I/P compartment lamp
4. The map lamps
5. The reading lamps
6. The vanity mirror lamps

Courtesy/Illuminated Entry Lamps

The courtesy/illuminated entry lamps, may be manually turned on or off by placing the interior lamp switch in the ON or OFF position. If a door is opened, the courtesy/illuminated entry lamps illuminate. After all the doors have been closed the courtesy/illuminated entry lamps will remain illuminated approximately 15 seconds. The courtesy/illuminated entry lamps will also turn on prior to any door being opened, and remain illuminated approximately 40 seconds when the driver removes the ignition key. If the interior lamp switch is turned on when the ignition key is OFF, or the interior lamp switch is left on when the ignition key is turned OFF the body control module (BCM) will turn off the courtesy lamps after approximately 10 minutes.

When the driver places the dome lamp defeat switch in the OFF position, the courtesy/illuminated entry lamps will be disabled; however, the lamps will still operate from the interior lamp switch.

The left and right front door courtesy lamps are controlled, and receive voltage and ground from the drivers door module (DDM) and the passenger door module (PDM), respectively. The BCM, DDM, and the PDM communicate through class II serial data for the lamp illumination commands and the door ajar switches.

The remaining courtesy lamps are controlled and receive voltage from the BCM. Ground is provided to the footwell lamps and all courtesy/reading lamps at G203. Ground is provided to the right middle and right rear door at G306. Ground is provided to the left middle and left rear door at G302.

Keyless Entry Interior Illumination

When the driver uses the door key in order to unlock the doors, the body control module (BCM) receives a door unlock signal. The BCM must have inputs that indicate that the ignition switch is OFF, the courtesy lamp switch is OFF, and all the doors are closed. The BCM will then activate the interior lamps. The courtesy lamps will remain on, approximately 15 seconds after the door is closed. The BCM will then turn them off through the theater dimming feature. If the door locks are activated to the LOCK position, or if the ignition switch is turned to either the RUN or CRANK position the courtesy lamps will turn off immediately.

When the driver uses the remote function actuator transmitter to unlock the doors, the trunk, or presses the panic button, the BCM will keep the courtesy lamps on approximately 40 seconds. When the driver uses the remote function actuator transmitter to lock the doors, the BCM will keep the courtesy lamps on approximately 2 seconds. If the ignition switch is turned to either the RUN or CRANK position, the courtesy lamps will turn off immediately. The BCM will also keep the courtesy lamps on approximately 40 seconds, after an alarm event is completed.

Vanity Lamps

The inadvertent power supply voltage circuit of the body control module (BCM) provides battery positive voltage to each vanity mirror lamp. When the vanity mirror cover on the sunshade is opened, a switch closes to provide a ground circuit and the vanity lamp illuminates. In the event that any of these lamps were to remain illuminated for a period of more than 10 minutes with the ignition switch in the OFF position, the BCM will deactivate the inadvertent power supply voltage circuit to prevent a total battery discharge condition. Ground is provided to the vanity lamps at G203.

I/P Compartment Lamp

The inadvertent power supply voltage circuit of the body control module (BCM) provides battery positive voltage to the instrument panel (I/P) compartment lamp. When the I/P compartment is opened, a switch closes to provide a ground circuit and the I/P compartment lamp illuminates. In the event that any of these lamps were to remain illuminated for a period of more than 10 minutes with the ignition switch in the OFF position, the BCM will deactivate the inadvertent power supply voltage circuit to prevent a total battery discharge condition. Ground is provided to the I/P compartment lamp at G203.

Reading Lamps

The inadvertent power supply voltage circuit of the body control module (BCM) provides battery positive voltage to the reading lamps. The reading lamps and switch are integral to the courtesy/reading lamp assembly. When the switch is closed, voltage is supplied and the lamp illuminates. In the event that any of these lamps were to remain illuminated for a period of more than 10 minutes with the ignition switch in the OFF position, the BCM will deactivate the inadvertent power supply voltage circuit to prevent a total battery discharge condition. Ground is provided to the reading lamps at G203.

Battery Rundown Protection/Inadvertent Power

The body control module (BCM) inadvertent power supply voltage circuit provides battery positive voltage to all of the interior reading lamps, instrument panel (I/P) compartment lamp, and both visor vanity mirror lamps. In the event that any of these lamps were to remain illuminated for a period of more than 10 minutes with the ignition switch in the OFF position, the BCM will deactivate the inadvertent power supply voltage circuit to prevent a total battery discharge condition.

The BCM also utilizes the inadvertent power supply voltage circuit as a lamp request signal circuit when none of the lamps in the circuit are illuminated. When a lamp switch is activated, the BCM receives the request for lamp illumination and switches to supplying voltage to the inadvertent power supply voltage circuit.

Interior Lamps Dimming

The second group includes lamps which may be dimmed. This group may use a combination of vacuum fluorescent (VF) illumination and incandescent lamps.

When the ignition switch is turned to the RUN position, the radio's VF displays turn on at maximum brightness. When the park lamps are on, all incandescent back lighting turns on at the dimming level indicated by the instrument panel (I/P) dimmer switch. At the same time all VF displays dim to match the indicated dimming level. The panel dimmer switch potentiometer is an input to the body control module (BCM). When the driver selects a dimming setting by moving the I/P dimming switch potentiometer, all incandescent back lighting lamps are provided with a specific voltage. When the I/P dimmer switch is moved from MIN to MAX, all VF displays, as well as all incandescent back lighting, respond from minimum intensity to maximum brightness in response to the I/P dimmer switch. The following switches and components have back lighting when the park lamps are on.

1. The instrument panel cluster (IPC)
2. The radio
3. The window and heated seat switches
4. The garage door opener switch
5. The sunroof switch
6. The HVAC control assemblies
7. The headlamp and panel dimmer switch
8. The tow/haul switch
9. The transfer case shift control switch
10. The height control switch
11. The PSIR disable switch
12. The PRNDL lamps
13. The traction control switch
14. The steering wheel control switches
15. The rear wiper/washer switch

The left and right front door switch illumination is controlled, receives voltage and ground from the drivers door module (DDM) and the passenger door module (PDM), respectively. The radio is also a class II module and has full control of its illumination. The BCM, DDM, PDM, and radio communicate through class II serial data for the lamp illumination commands.

The I/P cluster illumination lamps receive voltage and are controlled by the BCM on the instrument panel lamps dimming supply voltage circuit. Ground for the instrument panel lamps is at G203.

The various switches, HVAC control assembly, and the PRNDL lamps receive voltage, and are controlled by the BCM on the instrument panel lamps dimming control circuit. Ground for the rear window switches is at G302 and G306. Ground for the traction control switch, steering wheel controls, and the rear window/wiper switch is at G200. Ground for the remaining switches is at G203.

The following indicators receive voltage from the BCM and are controlled by various modules.

1. The traction control switch traction control OFF indicator
2. The height control switch high clearance indicator
3. The transfer case control switch 4WD position indicator
4. The heated seat indicators

The indicators receive voltage from the BCM on the LED dimming circuit. Ground/control for the indicators is from the various modules. The modules controlling the above indicators are as follows

1. The electronic brake control module (EBCM)
2. The air suspension module
3. The driver door module (DDM)
4. The passenger door module (BCM)