Lighting Systems Cadillac Escalade GMT800

Fastener Tightening Specifications

Lighting Systems Fastener Tightening Specifications

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Begin the system diagnosis with the DIAGNOSTIC SYSTEM CHECK - LIGHTING SYSTEMS . The Diagnostic System Check will provide the following information

1. The identification of the control module(s) which command the system.
2. The ability of the control module(s) to communicate through the serial data circuit.
3. The identification of any stored diagnostic trouble codes (DTCs) and their status.

The use of the Diagnostic System Check will identify the correct procedure for diagnosing the system and where the procedure is located.

Test Description

The number(s) below refer to the step number(s) on the diagnostic table.

1. 2. Lack of communication may be due to a partial malfunction of the class 2 serial data circuit or due to a total malfunction of the class 2 serial data circuit. The specified procedure will determine the particular condition.
2. 3. This step determines if an ignition switch power mode condition exists. The specified procedure will determine which diagnostic path is to be followed.
3. 4. This step determines if a Body Control Module (BCM) DTC based diagnostic path or a symptom based diagnostic path are to be followed.
4. 5. The presence of DTCs which begin with U indicate some other module is not communicating. The specified procedure will compile all the available information before tests are performed.
5. 6. This step displays stored system related DTCs to be diagnosed.

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Data

Backlight Dimming: The scan tool displays the duty cycle of the pulse width modulated (PWM) signal distributed by the BCM to the PWM controlled I/P backlighting based on the position of the I/P dimmer switch, thumbwheel. The scan tool displays 0 percent when the headlamp switch is in the AUTO position and the daytime running lamps (DRL) are ON or the I/P dimmer switch is in the FULL DIM position. The scan tool displays approximately 85 percent when either the low beam headlamps or park lamps are activated and the I/P dimmer switch is in the FULL BRIGHT position.

Battery Voltage: The scan tool displays the battery system voltage received by the module.

Dimming Input: The scan tool displays the voltage value indicating the position of the I/P dimmer switch, thumbwheel. The scan tool displays 4 volts when the headlamp switch is in the AUTO position and the daytime running lamps (DRL) are ON or the I/P dimmer switch is in the FULL DIM position. The scan tool displays 0 volts when either the park lamps or the headlamps are turned ON and the I/P dimmer switch is in the FULL BRIGHT position.

Dimming Level: The scan tool displays the duty cycle of the pulse width modulated (PWM) signal distributed by the BCM to the interior lighting circuits. The scan tool displays 0 percent when the interior lamps illumination is OFF. The scan tool displays 100 percent when the interior lamp illumination is at full intensity.

Indicator Dimming: The scan tool displays the duty cycle of the pulse width modulated (PWM) signal distributed by the BCM to the PWM controlled I/P backlighting based on the position of the I/P dimmer switch, thumbwheel. The scan tool displays 1.2 percent when the headlamp switch is in the AUTO position and the daytime running lamps (DRL) are ON or the I/P dimmer switch is in the FULL DIM position. The scan tool displays 100 percent when either the headlamps or park lamps are activated and the I/P dimmer switch is in the FULL BRIGHT position.

Light Sensor: The scan tool displays the output voltage of the ambient light sensor based on the intensity of light detected. As the light intensity increases, the sensor displayed voltage decreases. In the LIGHT state, a low voltage, not less than 1.75 volts, is present and the DRL will be ON. In the DARK state, a high voltage, up to 4.9 volts, is present and the headlamps will be ON.

Inputs

Courtesy Lamp Switch: The scan tool displays the position of the courtesy lamp switch. The scan tool displays Active when the switch is turned ON. The BCM uses this data in controlling the operation of the courtesy lamps.

Front Fog Lamp Switch: The scan tool the front fog lamp switch. The scan tool displays ACTIVE or INACTIVE when the switch is depressed. The BCM uses this data in controlling the operation of the front fog lamps.

Flash to Pass Switch: The scan tool displays the position of the flash to pass switch. The scan tool displays On when the switch is pulled to activate the high beams momentarily while the switch is held.

Headlamp Switch: The scan tool displays the position of the headlamp switch. The scan tool displays Active when the headlamp switch is in the ON position. The BCM uses this data in controlling the operation of the headlamps.

High Beam Switch: The scan tool displays the position of the high beam switch. The scan tool displays On when the switch is used to activate the high beams.

Ignition 0: The scan tool displays the position of the ignition switch. The scan tool displays On when the ignition switch is in the RUN or CRANK position.

Ignition 1: The scan tool displays the position of the ignition switch. The scan tool displays On when the ignition switch is in the RUN or CRANK position.

Ignition Accessory: The scan tool displays the position of the ignition switch. The scan tool displays On when the ignition switch is in the ACCY position only.

Inadvertent Power Relay: The scan tool displays the state of the inadvertent power battery rundown protection feature of the BCM. The scan tool displays Off when all inadvertent power circuits are functioning normally.

Interior Lamp Defeat Switch: The scan tool displays the position of the courtesy/dome lamp override switch. The scan tool displays On when the switch is activated requesting the BCM to override the normal interior lamp activation inputs and deactivate the interior lighting.

Key in Ignition: The scan tool displays Yes when the key has been inserted into the ignition switch. The scan tool displays No after the key has been removed.

Park Brake Switch: The scan tool displays the position of the park brake pedal. The scan tool displays Set when the park brake is engaged closing the switch. The BCM uses this data in controlling the operation of the park brake indicator, the reminder chime feature and the DRL system.

Park Lamp Switch: The scan tool displays the position of the park lamp switch. The scan tool displays ON when the park lamp switch is in the ON position. The BCM uses this data in controlling the operation of the park lamps.

Outputs

High Beams: The scan tool displays the commanded state of the high beam relay. The scan tool displays On when the BCM allows the high beam relay to go to ground activating the high beam headlamps.

Low Beams: The scan tool displays the commanded state of the low beam relay. The scan tool displays ON when the BCM allows the high beam relay to go to activate the low beam headlamps.

Park Lamp Relay: The scan tool displays the commanded state of the park lamp relay. The scan tool displays ON when the BCM allows the park lamp relay to activate the park lamps.

Dimming Level: The scan tool displays the commanded state of the interior dimmable lamps. The scan tool displays a percentage based on the position of the thumb wheel.

Daytime Running Lamps: The scan tool displays the commanded state of the daytime running lamps (DRL). The scan tool displays ON when the BCM allows the DRL relay to activate the DRL.

Output Control

Dimming Level: The scan tool displays the duty cycle of the pulse width modulated (PWM) signal distributed by the BCM to the interior lighting circuits. The scan tool displays 0 percent when the interior lamps illumination is OFF. The scan tool displays 100 percent when the interior lamp illumination is at full intensity.

Daytime Running Lamps: The scan tool displays the commanded state of the daytime running lamps (DRL). The scan tool displays On when the BCM illuminates the DRL.

Park Lamp Relay: The scan tool displays the commanded state of the park lamp relay. The scan tool displays On when the BCM allows the park lamp relay to go to ground to activate the park lamps.

Scheme 156

Circuit Description

The body control module (BCM) controls the illumination dimming of all of the control switch indicators. The BCM sets the control switch indicator illumination level according to the instrument panel (I/P) dimmer switch signal received when the component is activated and the indicator is ON. The BCM also activates the headlamp on indicator.

Voltage for the LED dimming signal, instrument panel lamps dimming control, as well as the instrument panel lamps dimming supply voltage circuits is from the TBC 2 A fuse in the instrument panel fuse block directly through the BCM to these circuits.

Conditions for Running the DTC

The battery voltage must be between 9.0-16.0 volts.

Conditions for Setting the DTC

1. The headlamp on indicator control circuit is open, shorted to ground, or shorted to voltage.
2. The LED dimming signal circuit is open, shorted to ground, or shorted to voltage.
3. The instrument panel lamps dimming control circuit is shorted to ground.
4. There is a loss of the instrument panel fuse block TBC 2 A battery supply voltage to the BCM for 1 second.

Diagnostic Aids

1. Perform a visual inspection for loose or poor connections at all related components. Refer to TESTING FOR INTERMITTENT AND POOR CONNECTIONS in Wiring Systems.
2. A short to ground in the following circuits will cause the TBC 2 A fuse to open. The instrument panel lamps dimming control. Battery positive voltage from the instrument panel fuse block TBC 2 A fuse.
3. An open in the TBC 2 A fuse will cause the BCM to set the following DTC: B0951 B2610 B2625

Action Taken When the DTC Sets

The headlamps on indicator will remain on with the headlamps off.

The headlamps on indicator will remain off with the headlamps on.

Conditions for Clearing the MIUDTC

1. This DTC will clear on current status after the condition for setting the fault is corrected.
2. A history DTC will clear after 100 consecutive ignition cycles without a fault present.
3. History and current DTCs can be cleared using a scan tool.

The numbers below refer to the step numbers on the diagnostic table.

1. 9. Determines if it is the headlamp on indicator circuit or the BCM.
2. 10. Determines if it is the headlamp on indicator circuit or the BCM.
3. 15. After replacement of the BCM you must calibrate the new module for proper operation.

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The body control module (BCM) supplies battery positive voltage to the individually controlled lamps. In the event that any of these lamps were to remain illuminated for more than 20 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.

Voltage for the inadvertent power supply voltage circuit is from the TBC 2C fuse in the instrument panel (I/P) fuse block directly through the BCM to this circuit.

The battery voltage must be between 9.0-16.0 volts.

1. The inadvertent power supply voltage circuit is shorted to ground for more than 1 second.
2. There is a loss of the instrument panel fuse block TBC 2C battery supply voltage to the BCM for 1 second while one or more of the lamps in the inadvertent power circuit has been activated.

The lamps on the inadvertent power supply voltage circuit will not operate

Conditions for Clearing the MIL/DTC

1. This DTC will clear on current status after the condition for setting the fault is corrected.
2. A history DTC will clear after 100 consecutive ignition cycles without a fault present.
3. History and current DTCs can be cleared using a scan tool.

1. Perform a visual inspection for loose or poor connections at all related components. Refer to TESTING FOR INTERMITTENT AND POOR CONNECTIONS in Wiring Systems.
2. A short to ground in the inadvertent power supply voltage circuit or the battery positive voltage circuit will cause the TBC 2C fuse to open.

The numbers below refer to the step numbers on the diagnostic table.

1. 3. This step test determines if the problem exists in the wiring or the BCM.
2. 5. After replacement of the BCM you must calibrate the new module for proper operation.

Scheme 159

The body control module (BCM) monitors the front fog lamp switch signal circuit in order to determine when the fog lamp relay is to be energized. When the BCM senses that the front fog lamp switch signal circuit is grounded momentarily by pressing the fog lamp switch, the BCM energizes the fog lamp relay by grounding the fog lamp relay control circuit.

The battery voltage must be between 9.0-16.0 volts.

When the front fog lamp switch signal circuit is shorted to ground for approximately 15 seconds.

The fog lamps will not operate.

1. This DTC will clear on current status after the condition for setting the fault is corrected.
2. A history DTC will clear after 100 consecutive ignition cycles without a fault present.
3. History and current DTC(s) can be cleared using a scan tool.

1. Test the fog lamp switch for sticking in the ON position.
2. Perform a visual inspection for loose or poor connections at all related components. Refer to TESTING FOR INTERMITTENT AND POOR CONNECTIONS in Wiring Systems.

Scheme 160

When the BCM senses that the front fog lamp switch signal circuit is grounded momentarily by pressing the front fog lamp switch, the BCM energizes the front fog lamp relay by grounding the front fog lamp relay control circuit. The front fog lamp indicator is also illuminated utilizing the same fog lamp relay control circuit.

The battery voltage must be between 9.0-16.0 volts.

1. When the BCM receives a front fog lamp switch OFF command and the front fog lamp relay control circuit is shorted to ground.
2. When the BCM receives a front fog lamp switch ON command and the front fog lamp relay control circuit is shorted to voltage or open.

The front fog lamps will not operate or will remain always on.

1. This DTC will clear on current status after the condition for setting the fault is corrected.
2. A history DTC will clear after 100 consecutive ignition cycles without a fault present.
3. History and current DTC(s) can be cleared using a scan tool.

The numbers below refer to the step numbers on the diagnostic table.

1. 2. Listen for an audible click when the front fog lamp relay operates. Depress the switch for both the ON and OFF states. Repeat as necessary.
2. 3. Tests for voltage at the coil side of the front fog lamp relay.
3. 4. Verifies that the body control module (BCM) is providing ground to the front fog lamp relay.
4. 5. Tests if ground is constantly being applied to the front fog lamp relay.
5. 6. Tests if there is opposing voltage present or an open in the front fog lamp relay control circuit.
6. 12. After replacement of the BCM you must calibrate the new module for proper operation.

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When the BCM senses that the rear fog lamp switch signal circuit is grounded momentarily by pressing the rear fog lamp switch, the BCM energizes the rear fog lamp relay by grounding the rear fog lamp relay control circuit. The rear fog lamp indicator is also illuminated utilizing the same fog lamp relay control circuit.

The battery voltage must be between 9.0-16.0 volts.

1. When the BCM receives a rear fog lamp switch OFF command and the rear fog lamp relay control circuit is shorted to ground.
2. When the BCM receives a rear fog lamp switch ON command and the rear fog lamp relay control circuit is shorted to voltage or open.

The rear fog lamps will not operate or will remain always on.

1. This DTC will clear on current status after the condition for setting the fault is corrected.
2. A history DTC will clear after 100 consecutive ignition cycles without a fault present.
3. History and current DTC(s) can be cleared using a scan tool.

The numbers below refer to the step numbers on the diagnostic table.

1. 2. Listen for an audible click when the rear fog lamp relay operates. Depress the switch for both the ON and OFF states. Repeat as necessary.
2. 3. Tests for voltage at the coil side of the rear fog lamp relay.
3. 4. Verifies that the body control module (BCM) is providing ground to the rear fog lamp relay.
4. 5. Tests if ground is constantly being applied to the rear fog lamp relay.
5. 6. Tests if there is opposing voltage present or an open in the rear fog lamp relay control circuit.
6. 12. After replacement of the BCM you must calibrate the new module for proper operation.

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When the body control module (BCM) receives a signal requesting to illuminate the backup lamps, battery voltage is sent directly from the BCM through the backup lamp supply voltage circuit to the backup lamps.

Voltage for the backup lamp supply voltage circuit as well as the courtesy lamp supply voltage circuit is from the left instrument panel fuse block TBC 2B 15 A fuse directly through the BCM to these circuits.

The battery voltage must be between 9.0-16.0 volts.

1. When the BCM receives a backup lamp request signal and the backup lamp supply voltage circuit is shorted to ground.
2. When the BCM is not receiving a backup lamp request signal and the backup lamp supply voltage circuit is open or shorted to voltage.
3. There is a loss of the instrument panel fuse block TBC 2B battery supply voltage to the BCM for 1 second.

The backup lamps will not operate.

1. This DTC will clear on current status after the condition for setting the fault is corrected.
2. A history DTC will clear after 100 consecutive ignition cycles without a fault present.
3. History and current DTCs can be cleared using a scan tool.

1. Perform a visual inspection for loose or poor connections at all related components. Refer to TESTING FOR INTERMITTENT AND POOR CONNECTIONS in Wiring Systems.
2. A short to ground on the backup lamp supply voltage circuit, courtesy lamp supply voltage circuit OR the TBC 2B battery positive voltage circuit to the BCM will open the TBC 2B fuse in the left instrument panel fuse block.

The numbers below refer to the step numbers on the diagnostic table.

1. 3. This step test determines if the problem exists in the wiring or the BCM.
2. 4. This step test determines if the problem exists in the wiring or the BCM.
3. 5. After replacement of the BCM you must calibrate the new module for proper operation.

Scheme 165

When the BCM senses a request for low beam headlamp illumination, the BCM sends a ground signal to the low beam headlamp relay through the headlamp low beam relay control circuit. The headlamp low beam relay will apply voltage to illuminate the headlamps.

The battery voltage must be between 9.0-16.0 volts.

1. When the BCM receives a command to illuminate the low beam headlamps and the headlamp low beam relay control circuit is open or shorted to voltage.
2. When the BCM does not receive a command to illuminate the low beam headlamps and the headlamp low beam relay control circuit is shorted to ground.
3. When the low beam relay coil side is open or the battery positive voltage to the low beam relay is open.

The low beam headlamps will not operate or will remain always on.

1. This DTC will clear on current status after the condition for setting the fault is corrected.
2. A history DTC will clear after 100 consecutive ignition cycles without a fault present.
3. History and current DTC(s) can be cleared using a scan tool.

The numbers below refer to the step numbers on the diagnostic table.

1. 3. Tests for voltage at the voltage supply side of the headlamp low beam relay.
2. 4. Verifies that the body control module (BCM) is providing ground to the headlamp low beam relay.
3. 5. Tests if ground is constantly being applied to the headlamp low beam relay.
4. 6. Tests if there is opposing voltage present or an open headlamp low beam relay control circuit.
5. 12. After replacement of the BCM you must calibrate the new module for proper operation.

Scheme 166

When the BCM receives a ground signal from the multifunction high beam or flash to pass (FTP) switch commanding to illuminate the high beam headlamps, the BCM will energize the high beam relay by grounding the high beam relay control circuit.

The battery voltage must be between 9.0-16.0 volts.

1. When the BCM receives a high beam headlamp OFF command and the high beam headlamp relay control circuit is shorted to ground.
2. When the BCM receives a high beam headlamp ON command and the high beam headlamp relay control circuit is shorted to voltage or open.
3. When the high beam relay coil side is open or the battery positive voltage to the high beam relay is open.

The high beam headlamps will not operate or will remain always on.

1. This DTC will clear on current status after the condition for setting the fault is corrected.
2. A history DTC will clear after 100 consecutive ignition cycles without a fault present.
3. History and current DTCs can be cleared using a scan tool.

The numbers below refer to the step numbers on the diagnostic table.

1. 2. Listen for an audible click when the high beam relay operates. Command both the ON and OFF states. Repeat the commands as necessary.
2. 3. Tests for voltage at the coil side of the high beam relay.
3. 4. Verifies that the body control module (BCM) is providing ground to the high beam relay.
4. 5. Tests if ground is constantly being applied to the high beam relay.
5. 6. Tests if there is opposing voltage present or an open high beam relay control circuit.
6. 12. After replacement of the BCM you must calibrate the new module for proper operation.

Scheme 167

When the body control module (BCM) receives a ground signal from the headlamp switch commanding to illuminate the park lamps, the BCM will energize the park lamp relay by grounding the park lamp relay control circuit.

The battery voltage must be between 9.0-16.0 volts.

1. When the park lamp relay control circuit is open or shorted to ground.
2. When the BCM receives a park lamp ON command and the park lamp relay control circuit is shorted to voltage.
3. When the park lamp relay coil side is open or the battery positive voltage to the low beam relay is open.

The park lamps will not operate or will remain always on.

1. This DTC will clear on current status after the condition for setting the fault is corrected.
2. A history DTC will clear after 100 consecutive ignition cycles without a fault present.
3. History and current DTC(s) can be cleared using a scan tool.

The numbers below refer to the step numbers on the diagnostic table.

1. 2. Listen for an audible click when the park lamp relay operates. Command both the ON and OFF states. Repeat the commands as necessary.
2. 3. Tests for voltage at the coil side of the park lamp relay.
3. 4. Verifies that the body control module (BCM) is providing ground to the park lamp relay.
4. 5. Tests if ground is constantly being applied to the park lamp relay.
5. 6. Tests if there is opposing voltage present or an open park lamp relay control circuit.
6. 12. After replacement of the BCM you must calibrate the new module for proper operation.

Scheme 168

The ambient light sensor is a light sensitive transistor that sends a variable voltage signal to the body control module (BCM) in response to the exterior light level. The BCM energizes the DRL relay by grounding the DRL relay control circuit. The DRL operate when the ambient light sensor indicates daytime, the ignition switch is in the RUN position an the gear selector is not in the park position.

The battery voltage must be between 9.0-16.0 volts.

1. When the BCM sends a DRL OFF command am the DRL relay control circuit is shorted to ground.
2. When the BCM sends a DRL ON command and the DRL relay control circuit is shorted to voltage or open.

The DRL will not operate or will remain always on.

1. This DTC will clear on current status after the condition for setting the fault is corrected.
2. A history DTC will clear after 100 consecutive ignition cycles without a fault present.
3. History and current DTCs can be cleared using a scan tool.

The numbers below refer to the step numbers on the diagnostic table.

1. 2. Listen for an audible click when the DRL relay operates. Command both the ON and OFF states. Repeat the commands as necessary.
2. 3. Tests for voltage at the coil side of the DRL relay.
3. 4. Verifies that the body control module (BCM) is providing ground to the DRL relay.
4. 5. Tests if ground is constantly being applied to the DRL relay.
5. 6. Tests if there is opposing voltage present or an open in the DRL relay control circuit.
6. 12. After replacement of the BCM you must calibrate the new module for proper operation.

Scheme 169

The body control module (BCM) receives a variable voltage signal from the instrument panel (I/P) dimmer switch requesting to illuminate the illumination lamps to a desired intensity. When this occurs, the BCM directly sends a variable voltage based on the I/P dimmer switch position on the instrument panel lamps dimming supply voltage circuit, instrument panel lamps dimming control circuit, and the LED dimming signal circuit.

Voltage for the instrument panel lamps dimming supply voltage circuit, instrument panel lamps dimming control circuit, and the LED dimming signal circuits is from the TBC 2 A fuse in the instrument panel fuse block directly through the BCM to these circuits.

The battery voltage must be between 9.0-16.0 volts.

1. The instrument panel lamps dimming control circuit is open, shorted to ground, or shorted to voltage.
2. The instrument panel lamps dimming supply voltage circuit is open, shorted to ground, or shorted to voltage.
3. There is a loss of the instrument panel fuse block TBC 2 A battery supply voltage to the BCM for 1 second.

The illumination lamps will not operate or are always ON.

1. This DTC will clear on current status after the condition for setting the fault is corrected.
2. A history DTC will clear after 100 consecutive ignition cycles without a fault present.
3. History and current DTCs can be cleared using a scan tool.

1. Perform a visual inspection for loose or poor connections at all related components. Refer to TESTING FOR INTERMITTENT AND POOR CONNECTIONS in Wiring Systems.
2. A short to ground in the following circuits will cause the TBC 2 A fuse to open. The instrument panel lamps dimming control. Battery positive voltage from the instrument panel fuse block TBC 2 A fuse.
3. An open in the TBC 2 A fuse will cause the BCM to set the following DTC: B0951 B2610 B2625

The numbers below refer to the step numbers on the diagnostic table.

1. 5. This step test determines if the problem exists in the headlamp switch or the BCM.
2. 10. After replacement of the BCM you must calibrate the new module for proper operation.

Scheme 170

The body control module (BCM) receives a ground signal from the door jamb, liftglass/liftgate if equipped, or courtesy lamp switches requesting courtesy/dome lamp illumination. When this occurs, the BCM directly sends a voltage through the courtesy lamp supply voltage circuit illuminating the courtesy/dome lamps.

Voltage for the courtesy lamp supply voltage circuit as well as the backup lamp supply voltage circuit is from the left instrument panel fuse block TBC 2B 15 A fuse directly through the BCM to these circuits.

The battery voltage must be between 9.0-16.0 volts.

1. When the BCM receives a courtesy lamp illumination request signal and the courtesy lamp supply voltage circuit is shorted to ground.
2. When the BCM is not receiving a courtesy lamp illumination request signal and the courtesy lamp supply voltage circuit is open only to the first splice from the BCM or the circuit is shorted to voltage.
3. There is a loss of the instrument panel fuse block TBC 2B battery supply voltage to the BCM for 1 second.

The courtesy dome lamps will not operate or are always ON.

1. This DTC will clear on current status after the condition for setting the fault is corrected.
2. A history DTC will clear after 100 consecutive ignition cycles without a fault present.
3. History and current DTCs can be cleared using a scan tool.

1. Perform a visual inspection for loose or poor connections at all related components. Refer to TESTING FOR INTERMITTENT AND POOR CONNECTIONS in Wiring Systems.
2. An open circuit up to the first splice only, from the BCM, will set the DTC.
3. A short to ground on the backup lamp supply voltage circuit, courtesy lamp supply voltage circuit OR the TBC 2B battery positive voltage circuit to the BCM will open the TBC 2B fuse in the left instrument panel fuse block.

The numbers below refer to the step numbers on the diagnostic table.

1. 3. This step test determines if the problem exists in the wiring or the BCM.
2. 4. This step test determines if the problem exists in the wiring or the BCM.
3. 5. After replacement of the BCM you must calibrate the new module for proper operation.

Scheme 171

The BCM directly sends a 5 volt reference voltage to the I/P dimmer switch which is then adjusted based on the I/P dimmer switch position and returned as a dimming return and dimming input to the BCM. The BCM uses this signal to directly control the desired level of instrument panel illumination lamp intensity.

The battery voltage must be between 9.0-16.0 volts.

1. The BCM monitors a dimming return voltage of less than 4.5 volts.
2. The BCM monitors a 5 volt reference voltage of greater than 5.5 volts.
3. The BCM monitors dimming input voltage of equal or greater than 4.86 volts for more than 1 second.

The instrument panel illumination lamp dimming will not operate.

1. This DTC will clear on current status after the condition for setting the fault is corrected.
2. A history DTC will clear after 100 consecutive ignition cycles without a fault present.
3. History and current DTCs can be cleared using a scan tool.

The numbers below refer to the step numbers on the diagnostic table.

1. 3. Tests for the proper operation of the circuit in the low voltage range.
2. 4. Tests for the proper operation of the circuit in the high voltage range. If the fuse in the jumper opens when you perform this test, the signal circuit is shorted to ground.
3. 5. Tests for a short to voltage in the 5 volt reference circuit.
4. 6. Tests for a high resistance or an open in the dimming return circuit.

Scheme 172

Scheme 173

The body control module (BCM) receives a variable voltage signal from the instrument panel (I/P) dimmer switch requesting to illuminate the dimming lamps to a desired intensity. When this occurs, the BCM directly sends a pulse width modulated (PWM) voltage based on the I/P dimmer switch position on the LED dimming supply circuit, instrument panel lamps dimming control circuit, and the instrument panel lamps dimming supply voltage circuit.

Voltage for the LED dimming supply circuit, instrument panel lamps dimming control circuit, and the instrument panel lamps dimming supply voltage circuit is from the TBC 2 A fuse in the instrument panel (I/P) fuse block directly through the BCM to these circuits.

The battery voltage must be between 9.0-16.0 volts.

1. The instrument panel lamps dimming control circuit is shorted to ground.
2. The LED dimming supply circuit is shorted to ground.
3. There is a loss of the I/P fuse block TBC 2 A fuse battery supply voltage to the BCM for 1 second.

All dimming lamps will not illuminate or the control switch ON/OFF indicators will not illuminate.

1. This DTC will clear on current status after the condition for setting the fault is corrected.
2. A history DTC will clear after 100 consecutive ignition cycles without a fault present.
3. History and current DTC(s) can be cleared using a scan tool.

1. Perform a visual inspection for loose or poor connections at all related components. Refer to TESTING FOR INTERMITTENT AND POOR CONNECTIONS in Wiring Systems.
2. A short to ground in the following circuits will cause the TBC 2 A fuse to open. The instrument panel lamps dimming control. Battery positive voltage from the I/P fuse block TBC 2 A fuse.
3. An open in the TBC 2 A fuse will cause the BCM to set the following DTC: B0951 B2610 B2625

The number below refers to the step number on the diagnostic table.

1. 4. After replacement of the BCM you must calibrate the new module for proper operation.

Scheme 174

The body control module (BCM) monitors the ambient light sensor signal circuit in order to determine if the daytime running lights (DRL) or the auto headlights (ALC) should be turned ON in the AUTO mode. When the BCM senses the ambient light sensor voltage is between 1.75 - 4.9 volts, either the DRL will be commanded ON or the ALC will be commanded ON.

The system voltage must be between 9.0 - 16.0 volts.

1. When the ambient light sensor signal voltage is less than 1.75 volts.
2. When the ambient light sensor signal voltage is more than 4.9 volts.

The ALC will remain ON in any ambient light state.

1. This DTC will clear immediately after the condition for setting the fault is corrected.
2. A history DTC will clear after 100 consecutive ignition cycles without a fault present.
3. Use a scan tool in order to clear history and current DTCs.

The numbers below refer to the step numbers on the diagnostic table.

1. 3. Tests for the proper operation of the circuit in the low voltage range.
2. 4. Tests for the proper operation of the circuit in the high voltage range. If the fuse in the jumper opens when you perform this test, the signal circuit is shorted to ground.
3. 5. Tests for a short to voltage in the ambient light sensor low reference circuit.
4. 13. After replacement of the BCM you must calibrate the new module for proper operation.

Scheme 175

Scheme 176

The body control module (BCM) monitors the courtesy lamp switch signal circuit in order to determine when the courtesy/dome lamps should be illuminated. When the BCM senses that the courtesy lamp switch signal circuit is grounded when the switch is activated, the BCM will illuminate the courtesy/dome lamps.

1. The BCM instrument panel dimmer switch reference voltage must be between 4.5-5.5 volts.
2. The battery voltage must be between 9.0-16.0 volts.

1. When the instrument panel dimmer switch signal is greater than 1.0 volt.
2. When the BCM receives a courtesy lamp ON request signal from the courtesy lamp switch.

The courtesy/dome lamps will not operate.

1. This DTC will clear on current status after the condition for setting the fault is corrected.
2. A history DTC will clear after 100 consecutive ignition cycles without a fault present.
3. History and current DTCs can be cleared using a scan tool.

1. Test the courtesy lamp switch for sticking in the ON position.
2. Perform a visual inspection for loose or poor connections at all related components. Refer to TESTING FOR INTERMITTENT AND POOR CONNECTIONS in Wiring Systems.

Scheme 177

The body control module (BCM) monitors the park lamp switch on signal circuit and the headlamp switch headlamps on signal circuit in order to determine when the park lamps and headlamps should be illuminated. When the headlamp switch is turned to PARK, the BCM senses that the park lamp switch signal on circuit is grounded and the headlamps switch headlamps ON signal circuit is open. The BCM will then energize the park lamp relay illuminating the park lamps. When the headlamp switch is turned to HEAD, the BCM senses that the park lamp switch on signal circuit and the headlamp switch headlamps ON signal circuit are grounded. The BCM will then energize the park lamp relay and headlamp low beam relay or high beam relay illuminating the park lamps and headlamps.

The battery voltage must be between 9.0-16.0 volts.

When the headlamp switch park lamps on signal circuit is open or has a high resistance.

When the headlamp switch headlamps on signal circuit is shorted to ground.

The park lamps will not operate or the headlamps will illuminate without the park lamps.

1. This DTC will clear on current status after the condition for setting the fault is corrected.
2. A history DTC will clear after 100 consecutive ignition cycles without a fault present.
3. History and current DTCs can be cleared using a scan tool.

Scheme 178

Scheme 179

1. Perform the «DIAGNOSTIC SYSTEM CHECK - LIGHTING SYSTEMS»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-lights/#lighting-systems) before using the Symptom Tables in order to verify that all of the following are true: There are no DTCs set. The control modules can communicate via the serial data link.
2. Review the system operation in order to familiarize yourself with the system functions. Refer to the following: «EXTERIOR LIGHTING SYSTEMS DESCRIPTION AND OPERATION»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-lights/#lighting-systems) «INTERIOR LIGHTING SYSTEMS DESCRIPTION AND OPERATION»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-lights/#lighting-systems)

Visual/Physical Inspection

1. Inspect for aftermarket devices which could affect the operation of the Lighting System. Refer to CHECKING AFTERMARKET ACCESSORIES in Wiring Systems.
2. Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.

Intermittent

Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to TESTING FOR INTERMITTENT AND POOR CONNECTIONS in Wiring Systems.

Symptom List

Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom

1. «BACKUP LAMPS ALWAYS ON»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-lights/#lighting-systems)
2. «BACKUP LAMPS INOPERATIVE»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-lights/#lighting-systems)
3. «CARGO LAMP ALWAYS ON»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-lights/#lighting-systems)
4. «CARGO LAMP INOPERATIVE»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-lights/#lighting-systems)
5. «CLEARANCE LAMPS INOPERATIVE»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-lights/#lighting-systems)
6. «COURTESY LAMPS ALWAYS ON»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-lights/#lighting-systems)
7. «COURTESY LAMPS INOPERATIVE»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-lights/#lighting-systems)
8. «DAYTIME RUNNING LAMPS (DRL) ALWAYS ON»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-lights/#lighting-systems)
9. «DAYTIME RUNNING LAMPS (DRL) INOPERATIVE»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-lights/#lighting-systems)
10. «EXTERIOR COURTESY LAMP(S) ALWAYS ON»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-lights/#lighting-systems)
11. «EXTERIOR COURTESY LAMP(S) INOPERATIVE»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-lights/#lighting-systems)
12. «FOG LAMP INDICATOR INOPERATIVE»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-lights/#lighting-systems)
13. «FOG LAMP INDICATOR INOPERATIVE - REAR»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-lights/#lighting-systems)
14. «FOG LAMPS ALWAYS ON»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-lights/#lighting-systems)
15. «FOG LAMPS INOPERATIVE»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-lights/#lighting-systems)
16. «FOG LAMPS ALWAYS ON - REAR»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-lights/#lighting-systems)
17. «FOG LAMPS INOPERATIVE - REAR»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-lights/#lighting-systems)
18. «HAZARD LAMPS ALWAYS ON»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-lights/#lighting-systems)
19. «HAZARD LAMPS INOPERATIVE»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-lights/#lighting-systems)
20. «HEADLAMP SWITCH ON INDICATOR ALWAYS ON»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-lights/#lighting-systems)
21. «HEADLAMP SWITCH ON INDICATOR INOPERATIVE»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-lights/#lighting-systems)
22. «HEADLAMPS ALWAYS ON - LOW OR HIGH BEAM»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-lights/#lighting-systems)
23. «HEADLAMPS INOPERATIVE - HIGH BEAMS»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-lights/#lighting-systems)
24. «HEADLAMPS INOPERATIVE - LOW BEAMS (EXCEPT ESCALADE)»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-lights/#lighting-systems) or «HEADLAMPS INOPERATIVE - LOW BEAMS (ESCALADE)»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-lights/#lighting-systems)
25. «HEADLAMPS INOPERATIVE - LOW AND HIGH BEAMS»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-lights/#lighting-systems)
26. «HEADLAMPS INOPERATIVE - FLASH TO PASS»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-lights/#lighting-systems)
27. «HIGH BEAM INDICATOR ALWAYS ON»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-lights/#lighting-systems)
28. «HIGH BEAM INDICATOR INOPERATIVE»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-lights/#lighting-systems)
29. «INTERIOR BACKLIGHTING DOES NOT DIM»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-lights/#lighting-systems)
30. «INTERIOR BACKLIGHTING INOPERATIVE»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-lights/#lighting-systems)
31. «INSTRUMENT PANEL (I/P) COMPARTMENT LAMP INOPERATIVE»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-lights/#lighting-systems)
32. «INSTRUMENT PANEL (I/P) COMPARTMENT LAMP ALWAYS ON»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-lights/#lighting-systems)
33. «PARK, LICENSE, AND TAIL LAMPS ALWAYS ON»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-lights/#lighting-systems)
34. «PARK, LICENSE, AND TAIL LAMPS INOPERATIVE»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-lights/#lighting-systems)
35. «READING LAMP(S) INOPERATIVE»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-lights/#lighting-systems)
36. «STOP LAMPS ALWAYS ON»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-lights/#lighting-systems)
37. «STOP LAMPS INOPERATIVE»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-lights/#lighting-systems)
38. «TURN SIGNAL LAMPS AND/OR INDICATORS ALWAYS ON OR FLASHING»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-lights/#lighting-systems)
39. «TURN SIGNAL LAMPS AND/OR INDICATORS INOPERATIVE»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-lights/#lighting-systems)
40. «VANITY MIRROR LAMP(S) INOPERATIVE»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-lights/#lighting-systems)

Scheme 180

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Scheme 210

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Scheme 217

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Scheme 221

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Scheme 223

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Scheme 227

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Scheme 236

Scheme 237

Scheme 238

Scheme 239

Scheme 240

Scheme 241

Scheme 242

Scheme 243

Scheme 244

Removal Procedure

1. Disconnect the electrical connector from the stop lamp switch (2).
2. Remove the pushrod retaining clip (4).
3. Remove the stop lamp switch (2).

Installation Procedure

1. Install the stop lamp switch (2).
2. Install the pushrod retaining clip (4).
3. Connect the electrical connector to the stop lamp switch (2).

Scheme 245

Scheme 246

1. Remove the instrument cluster bezel. Refer to INSTRUMENT PANEL CLUSTER (IPC) REPLACEMENT in Instrument Panel, Gages and Console.
2. Unsnap the switch from the housing.
3. Disconnect the electrical connectors.
4. Remove the switch.

1. Connect the electrical connectors.
2. Install the headlamp switch by snapping the headlamps switch into place.
3. Install the bezel to the instrument panel. Refer to INSTRUMENT PANEL CLUSTER (IPC) REPLACEMENT in Instrument Panel, Gages and Console.

1. Remove the instrument panel bezel. Refer to BEZEL REPLACEMENT - INSTRUMENT PANEL (I/P) CLUSTER in Instrument Panel, Gages, and Console.
2. Pull out the accessary switch housing.
3. Disconnect the electrical connectors.
4. Remove the head lamp leveling switch from the accessary switch housing.

1. Install the head lamp leveling switch into accessary switch housing.
2. Connect the electrical connectors.
3. Install the accessary switch housing.
4. Install the instrument panel bezel. Refer to BEZEL REPLACEMENT - INSTRUMENT PANEL (I/P) CLUSTER in Instrument Panel, Gages, and Console.

1. Remove the instrument cluster bezel. Refer to INSTRUMENT PANEL CLUSTER (IPC) REPLACEMENT in Instrument Panel, Gages and Console.
2. Remove the fog lamp switch and cargo switch from the housing.
3. Disconnect the electrical connector(s) from the fog lamp switch.
4. Remove the fog lamp and cargo lamp switch from the housing.

1. Connect the electrical connector(s) to the fog lamp and cargo lamp switch.
2. Install the fog lamp switch into the housing.
3. Install the IP trim bezel to the instrument panel. Refer to INSTRUMENT PANEL CLUSTER (IPC) REPLACEMENT in Instrument Panel, Gages and Console.

1. Remove the instrument panel bezel. Refer to BEZEL REPLACEMENT - INSTRUMENT PANEL (UP) CLUSTER in Instrument Panel, Gages, and Console.
2. Pull out the accessary switch housing.
3. Disconnect the electrical connectors.
4. Remove the fog lamp switch from the accessary switch housing.

1. Install the fog lamp switch into accessary switch housing.
2. Connect the electrical connectors.
3. Install the accessary switch housing.
4. Install the instrument panel bezel. Refer to BEZEL REPLACEMENT - INSTRUMENT PANEL (I/P) CLUSTER in Instrument Panel, Gages, and Console.

Scheme 247

1. Remove the instrument panel top cover. Refer to INSTRUMENT PANEL (I/P) CARRIER REPLACEMENT in Instrument Panel, Gages and Console.
2. Disconnect the electrical connector (1) to the ambient light sensor on the underside of the IP top cover.
3. Turn the ambient light sensor 1/4 turn and remove it from the IP top cover.

1. Install the ambient light sensor to the underside of the IP top cover, turning it 1/4 turn to secure it in place.
2. Connect the electrical connector (1) to the ambient light sensor on the underside of the IP top cover.
3. Install the instrument panel top cover. Refer to INSTRUMENT PANEL (I/P) CARRIER REPLACEMENT in Instrument Panel, Gages and Console.

1. Use a flat-bladed tool in order to pry off the exterior courtesy lamp assembly.
2. Disconnect the electrical wires.
3. Remove the 2 retaining screws.
4. Remove the bulb.

1. Install the bulb. NOTE: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.
2. Install the 2 retaining screws. Tighten Tighten the screws to 2 N.m (17 lb in).
3. Connect the electrical wires.
4. Install the exterior courtesy lamp into the rear view mirror pressing into place until fully seated.

1. Gently push the assembly toward the front edge of the door.
2. Lift the rear of the assembly from the door by using a small flat tool.
3. Remove the courtesy lamp/reflector from the door panel.
4. Twist and remove the socket container from the housing.
5. Remove the bulb from the socket (if replacement is required).

1. Install the bulb into the socket.
2. Install the lens to the vehicle.
3. Install the bulb and socket assembly into the housing into the lens (if equipped).
4. Insert the tab on the assembly into the slot in the door panel at the front edge.
5. Pivot the assembly into the door panel.
6. Press the lens at the rear until the lens snaps into place.

1. Lower the instrument panel storage compartment door by pressing in the tab.
2. With one hand holding the plunger of the switch, use a small screw driver to push in the tabs on each side while pulling outwards.
3. Pull the switch assembly from the I/P.
4. Disconnect the electrical connector.
5. Remove the bulb (1).

1. Install the bulb (1) into the socket.
2. Connect the electrical connector.
3. Install the switch until the tabs (1) click in place.
4. Close the compartment door.

1. Remove the lamp lens assembly using a small screw driver.
2. Remove the dome lamp assembly from the headliner.
3. Disconnect the electrical connector.
4. Remove the bulb.

1. Install the bulb.
2. Connect the electrical connector.
3. Install the dome lamp assembly into the headliner.
4. Press the lens into place.

1. Disconnect the electrical connector.
2. Squeeze the lower tab. Remove the underhood lamp from the hood.
3. Remove the lens cover. Use a small flat bladed tool in order to pry the cover off.
4. Remove the bulb from the socket.

1. Install the bulb to the socket.
2. Install the lens cover.
3. Install the underhood lamp to the hood.
4. Connect the in-line electrical connector.

Note. When removing or replacing the arc tube, the arc tube must not contact the side of the headlamp housing or the bulb shield. Damage to the arc tube may result.

Scheme 248

1. Disconnect the battery negative cable. Refer to BATTERY NEGATIVE CABLE DISCONNECT/CONNECT PROCEDURE in Engine Electrical.
2. Remove the headlamp. Refer to «HEADLAMP ASSEMBLY OR HEADLAMP BULB REPLACEMENT (EXCEPT AVALANCHE)»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-lights/#lighting-systems) or «HEADLAMP ASSEMBLY OR HEADLAMP BULB REPLACEMENT (AVALANCHE)»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-lights/#lighting-systems) or «HEADLAMP ASSEMBLY OR HEADLAMP BULB REPLACEMENT (CADILLAC)»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-lights/#lighting-systems) or «HEADLAMP ASSEMBLY OR HEADLAMP BULB REPLACEMENT (HID)»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-lights/#lighting-systems) .
3. Remove the arc tube cover from the headlamp housing.
4. Disconnect the electrical connector (1) from the arc tube.
5. Remove the arc tube by pressing retaining clip (2) downward to release clip.
6. Remove arc tube.

1. Install arc tube into the headlamp housing.
2. Press down on retaining clip (2) to lock arc tube in place and reconnect electrical connector (1).
3. Install the arc tube cover to the headlamp housing.
4. Install the headlamp to the vehicle. Refer to «HEADLAMP ASSEMBLY OR HEADLAMP BULB REPLACEMENT (EXCEPT AVALANCHE)»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-lights/#lighting-systems) or «HEADLAMP ASSEMBLY OR HEADLAMP BULB REPLACEMENT (AVALANCHE)»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-lights/#lighting-systems) or «HEADLAMP ASSEMBLY OR HEADLAMP BULB REPLACEMENT (CADILLAC)»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-lights/#lighting-systems) or «HEADLAMP ASSEMBLY OR HEADLAMP BULB REPLACEMENT (HID)»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-lights/#lighting-systems) .
5. Connect the battery negative cable. Refer to BATTERY NEGATIVE CABLE DISCONNECT/CONNECT PROCEDURE in Engine Electrical.

Note. Avoid touching the bulb or letting the bulb come in contact with anything damp. Oil from your skin or moisture on the bulb can cause the bulb to explode when the bulb is turned on. If either comes in contact with the bulb, clean the bulb with alcohol or a suitable degreaser and wipe the bulb dry.

1. Open the hood.
2. Rotate the headlamp retainer pins outward.
3. Remove the headlamp retainer pins.
4. Pull out the headlamp assembly in order to access the electrical connector.
5. Disconnect the electrical connector.
6. Remove the bulb from the headlamp assembly by twisting the bulb counterclockwise.

1. Install the new bulb to the headlamp assembly by twisting the bulb clockwise in order to lock in place.
2. Connect the electrical connector to the bulb.
3. Install the headlamp assembly.
4. Install the headlamp retainer pins.
5. Rotate inward and lock the pins in place.
6. Inspect the operation.

Note. Avoid touching the bulb or letting the bulb come in contact with anything damp. Oil from your skin or moisture on the bulb can cause the bulb to explode when the bulb is turned on. If either comes in contact with the bulb, clean the bulb with alcohol or a suitable degreaser and wipe the bulb dry.

1. Open the hood.
2. Remove the park/turn signal lamp assembly. Refer to «PARK/TURN SIGNAL LAMP REPLACEMENT (EXCEPT AVALANCHE)»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-lights/#lighting-systems) or «PARK/TURN SIGNAL LAMP REPLACEMENT (AVALANCHE)»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-lights/#lighting-systems) .
3. Remove the headlamp retainer pins.
4. Pull out the headlamp assembly in order to access the electrical connector.
5. Disconnect the electrical connector.
6. Remove the bulb from the headlamp assembly by twisting the bulb counterclockwise.

1. Install the new bulb to the headlamp assembly by twisting the bulb clockwise in order to lock in place.
2. Connect the electrical connector to the bulb.
3. Install the headlamp assembly.
4. Install the headlamp retainer pins.
5. Rotate and lock the pins in place.
6. Install the park/turn signal lamp assembly. Refer to «PARK/TURN SIGNAL LAMP REPLACEMENT (EXCEPT AVALANCHE)»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-lights/#lighting-systems) or «PARK/TURN SIGNAL LAMP REPLACEMENT (AVALANCHE)»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-lights/#lighting-systems) .
7. Inspect the operation.

Note. Avoid touching the bulb or letting the bulb come in contact with anything damp. Oil from your skin or moisture on the bulb can cause the bulb to explode when the bulb is turned on. If either comes in contact with the bulb, clean the bulb with alcohol or a suitable degreaser and wipe the bulb dry.

1. Remove the front grille. Refer to GRILLE REPLACEMENT (CADILLAC) or GRILLE REPLACEMENT (AVALANCHE) in Exterior Trim.
2. Remove the headlamp retainer pins.
3. Pull out the headlamp assembly in order to access the electrical connector.
4. Disconnect the electrical connector.
5. Remove the rubber cup to gain access the headlamp bulbs.
6. Remove the bulbs.

1. Install the bulbs.
2. Install the rubber cup.
3. Connect the electrical connector to the lamp assembly.
4. Install the lamp assembly to the vehicle.
5. Install the headlamp assembly retainer pins.
6. Install the front grille. Refer to GRILLE REPLACEMENT (CADILLAC) or GRILLE REPLACEMENT (AVALANCHE) in Exterior Trim.

Scheme 249

Note. When removing or replacing the arc tube, the arc tube must not contact the side of the headlamp housing or the bulb shield. Damage to the arc tube may result.

1. Remove the front grille. Refer to GRILLE REPLACEMENT (CADILLAC) or GRILLE REPLACEMENT (AVALANCHE) in Exterior Trim.
2. Remove the headlamp retainer pins.
3. Pull out the headlamp assembly in order to access the electrical connector.
4. Disconnect the electrical connector.
5. Remove the rubber cups to gain access to the headlamp bulbs.
6. Remove the bulbs.

1. Install the bulbs.
2. Install the lamp assembly to the vehicle.
3. Install the rubber cups.
4. Connect the electrical connector to the lamp assembly.
5. Install the headlamp assembly retainer pins.
6. Install the front grille. Refer to GRILLE REPLACEMENT (CADILLAC) or GRILLE REPLACEMENT (AVALANCHE) in Exterior Trim.

Screen Method for Headlamp Aiming (Visual Aim)

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

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.

Scheme 250

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.

Scheme 251

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 must be fully assembled and all other work stopped while the headlamp aiming is being done.
4. The vehicle must contain one person or approximately 73 kg (160 lb).
5. Tires should be properly inflated.
6. Rock the vehicle to stabilize the suspension.
7. Measure from the floor to the center of the low beam bulb (2) on the vehicle.
8. At the screen, measure from the floor and place the horizontal tape at the above 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 above 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 above measured distance.
13. Turn the low beam headlamps ON.
14. The graphic shows the vertical (1) and horizontal (2) adjustments. Adjust the headlamps to the specifications required by state and local authorities. Ensure the horizontal adjustment scale is set to zero before adjusting the vertical aim.
15. The beam pattern must look as shown in the graphic. Important: Do not place a cover directly in front of the headlamp assembly while the headlamp is ON.
16. Adjust one headlamp at a time while blocking the light from the other. The cover must be away from the headlamp. The following list refers to the callouts in the graphic: Distance from ground to low beam bulb centerline (1) The ground line (2) Horizontal centerline of the low beam headlamp (3) Vertical centerline of the low beam headlamp (4) Two degrees or 26.7 cm (10.5 in) (5) to the right of the vehicle centerline (4)

Headlamp Aiming (Except Cadillac)

Tools Required: J25300-D Headlamp Aimer

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.

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

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.

Scheme 252

Scheme 253

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.

1. Disconnect the electrical connector from the fog lamp.
2. Remove the push pin retainers that attach the fog lamp to the bracket.
3. Remove the fog lamp adjuster bolt and spring from the adjuster nut.
4. Remove the fog lamp from the fog lamp bracket.
5. Remove the fog lamp bracket bolts and bracket, as needed.

Note. Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

1. Install the fog lamp bracket bolts and bracket, as needed. Tighten Tighten the bolt to 25 N.m (18 lb ft).
2. Install the fog lamp to the fog lamp bracket.
3. Install the fog lamp adjuster bolt and spring to the adjuster nut.
4. Install the push pin retainers that attach the fog lamp to the bracket.
5. Connect the electrical connector to the fog lamp.
6. Inspect the fog lamp aiming.

1. Disconnect the electrical connectors from the fog lamps.
2. Remove the 2 nuts from the back of the fog lamps.
3. Remove fog lamps from the lower fascia.

1. Install the fog lamps into the lower fascia. NOTE: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.
2. Install the 2 nuts on the back of the fog lamps. Tighten Tighten the nuts to 9 N.m (80 lb in).
3. Connect the electrical connectors to the fog lamps.

1. Remove the electrical connector. NOTE: Refer to Halogen Bulb Caution In Cautions and Notices.
2. Remove the bulb from the fog lamp assembly by twisting the bulb counterclockwise and pulling the bulb out.

1. Install the bulb to the fog lamp assembly by inserting the bulb and twisting the bulb clockwise.
2. Install the electrical connector.

1. Remove rear fog lamp retaining bolt (2) from the fog lamp bracket.
2. Disconnect the electrical connector from the rear fog lamp assembly.
3. Remove the fog lamp assembly (1) from the vehicle.

Scheme 254

1. Install the fog lamp assembly (1) to the bracket. CAUTION: Halogen bulbs contain gas under pressure. Handling a bulb improperly could cause it to shatter into flying glass fragments. To help avoid personal injury: Turn off the lamp switch and allow the bulb to cool before changing the bulb. Leave the lamp switch OFF until the bulb change is complete. Always wear eye protection when changing a halogen bulb. Handle the bulb only by its base. Avoid touching the glass. Keep dirt and moisture off the bulb. Properly dispose of the used bulb. Keep halogen bulbs out of the reach of children.
2. Install the fog lamp retaining bolt (2). Tighten Tighten the bolt to 25 N.m (18 lb ft).
3. Connect the electrical connector to the fog lamp assembly.
4. Inspect the fog lamp aiming.

1. Remove the rear fog lamp lens (1) retaining screws (2). CAUTION: Refer to Halogen Bulb Caution in Cautions and Notices.
2. Remove the bulb from the rear fog lamp assembly by twisting the bulb counterclockwise and pulling the bulb out.

Scheme 255

1. Install the bulb to the rear fog lamp assembly by inserting the bulb and twisting the bulb clockwise. NOTE: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.
2. Install the rear fog lamp lens (1) retaining screws (2). Tighten Tighten the screws (2) to 2 N.m (18 lb in).
3. Inspect the operation of the rear fog lamp.

Scheme 256

1. Raise and suitably support the vehicle.
2. Disconnect the electrical harness connectors. CAUTION: Halogen bulbs contain gas under pressure. Handling a bulb improperly could cause it to shatter into flying glass fragments. To help avoid personal injury: Turn off the lamp switch and allow the bulb to cool before changing the bulb. Leave the lamp switch OFF until the bulb change is complete. Always wear eye protection when changing a halogen bulb. Handle the bulb only by its base. Avoid touching the glass. Keep dirt and moisture off the bulb. Properly dispose of the used bulb. Keep halogen bulbs out of the reach of children.
3. Remove the bulbs from the daytime running and fog lamp assembly by turning the bulb 1/4 turn counterclockwise.
4. Remove the fasteners retaining the lamp assembly to the fascia.
5. Remove the lamp assembly from the vehicle.

1. Install the lamp assembly to the vehicle. NOTE: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.
2. Install the fasteners to the lamp assembly. Tighten Tighten the fasteners to 1.1 N.m (10 lb in).
3. Install the bulbs to the daytime running and fog lamp assembly by turning the bulb 1/4 turn clockwise.
4. Connect the electrical harness connectors.
5. Lower the vehicle.
6. Re-aim the fog lamps. Refer to «FOG LAMP AIMING PROCEDURE»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-lights/#lighting-systems__fog-lamp-aiming-procedure) .

Fog Lamp Aiming Procedure

The front fog lamps must be aimed for proper illumination of the road. The front fog lamp aim should be checked when a new front fog lamp assembly is installed, or if service or repairs in the front end area may have disturbed the front fog lamp mounting.

Preparation Procedure

Important: Horizontal aim is not adjustable on this vehicle. Vertical aim is adjusted by an adjusting nut located on the rear of the fog lamp. Prior to aiming the headlamps, perform the following steps

1. Completely assemble all of the components on the vehicle.
2. Park the vehicle on a level surface.
3. Stop all unnecessary operations or work on the vehicle that affect the vehicle trim.
4. Close the doors and ensure that the vehicle has no load other than the driver.
5. Stabilize the suspension by rocking the vehicle sideways.
6. Ensure that the fuel level is 1/2 full.
7. Ensure that the tires are inflated to the proper pressure.
8. Ensure that the driver or a similar weight, approximately 75 kg (165 lb), is in the vehicle driver seat.

Scheme 257

Scheme 258

1. Park the vehicle on a level surface 7.6 m (25 ft) away from a wall or other flat surface.
2. Measure the distance from the floor to the center of the fog lamp (5).
3. Using this measurement, mark the horizontal centerline of the fog lamp (1) on the flat surface directly in front of the vehicle.
4. Turn ON the fog lamps.
5. Reach under the rear lower edge of the front fascia in order to access the fog lamp vertical adjustment screw on the rear of the fog lamp.
6. Adjust the fog lamp so that the top edge of the fog lamp beam pattern is 100 mm (4 in) below the horizontal centerline.
7. Turn OFF the fog lamps.

Scheme 259

Scheme 260

Scheme 261

1. Locate the marker lamp gasket towards the wheel and gently lift the gasket edge to expose the service slot.
2. Insert a stiff wire as shown into the slot and push to release the marker lamp (1,3) locking tab from the flare.
3. Grasp the marker lamp (1,3) and pull towards the wheel to remove.
4. To remove the bulb socket from the marker lamp, turn the socket counterclockwise.
5. Pull the bulb to remove the bulb socket.

Scheme 262

Scheme 263

1. To install the bulb, gently push until seated into the bulb socket.
2. To install the bulb socket to the marker lamp, turn the socket clockwise.
3. Insert the marker lamp (1,3) tab and then press to secure locking tab to flare.

1. Locate the marker lamp gasket towards the wheel and gently lift the gasket edge to expose the service slot.
2. Insert a stiff wire as shown into the slot and push to release the marker lamp (1,3) locking tab from the flare.
3. Grasp the marker lamp (1,3) and pull towards the wheel to remove.
4. To remove the bulb socket from the marker lamp, turn the socket counterclockwise.
5. Pull the bulb to remove the bulb socket.

1. To install the bulb, gently push until seated into the bulb socket.
2. To install the bulb socket to the marker lamp, turn the socket clockwise.
3. Insert the marker lamp tab (1,3) and then press to secure locking tab to flare.

1. Ensure the headlamp switch is in the OFF position.
2. Remove the headlamp. Refer to «HEADLAMP ASSEMBLY OR HEADLAMP BULB REPLACEMENT (EXCEPT AVALANCHE)»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-lights/#lighting-systems) or «HEADLAMP ASSEMBLY OR HEADLAMP BULB REPLACEMENT (AVALANCHE)»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-lights/#lighting-systems) or «HEADLAMP ASSEMBLY OR HEADLAMP BULB REPLACEMENT (CADILLAC)»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-lights/#lighting-systems) or «HEADLAMP ASSEMBLY OR HEADLAMP BULB REPLACEMENT (HID)»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-lights/#lighting-systems) .
3. Remove the park/turn signal lamp assembly by pushing on the inboard retainer clip.
4. Disconnect the electrical connector from the park/turn signal lamp.

1. Connect the electrical connector to the park/turn signal lamp.
2. Install the lamp assembly.
3. Install the headlamp. Refer to «HEADLAMP ASSEMBLY OR HEADLAMP BULB REPLACEMENT (EXCEPT AVALANCHE)»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-lights/#lighting-systems) or «HEADLAMP ASSEMBLY OR HEADLAMP BULB REPLACEMENT (AVALANCHE)»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-lights/#lighting-systems) or «HEADLAMP ASSEMBLY OR HEADLAMP BULB REPLACEMENT (CADILLAC)»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-lights/#lighting-systems) or «HEADLAMP ASSEMBLY OR HEADLAMP BULB REPLACEMENT (HID)»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-lights/#lighting-systems) .

1. Open the hood.
2. Rotate the park/turn retainer pins.
3. Remove the park/turn retainer pins.
4. Pull out the park/turn assembly in order to access the electrical connector.
5. Disconnect the electrical connector.
6. Remove the bulb from the park/turn assembly by twisting the bulb counterclockwise.

1. Install the new bulb to the park/turn assembly by twisting the bulb clockwise in order to lock in place.
2. Connect the electrical connector to the bulb.
3. Install the park/turn assembly.
4. Install the park/turn retainer pins.
5. Rotate and lock the pins in place.
6. Inspect the operation.

1. Ensure the headlamp switch is in the OFF position.
2. Remove the upper garnish molding at the headliner. Refer to GARNISH MOLDING REPLACEMENT - REAR UPPER (AVALANCHE / ESCALADE EXT) or GARNISH MOLDING REPLACEMENT - REAR UPPER (TAHOE / YUKON / ESCALADE / SUBURBAN) in Interior Trim.
3. Remove the right and left side rear window garnish molding.
4. Lower the rear of the headliner in order to access the electrical connector.
5. Disconnect the electrical connector (4).
6. Attach a short piece of wire to the high mounted stop lamp connector in order to assist the guiding of the harness through the body.
7. Remove the high mounted stop lamp screws (2).
8. Remove the high mounted stop lamp (1) from the vehicle.

1. Attach the harness to the guide wire.
2. Using the guide wire, pull the lamp wire through the hole in the roof panel.
3. Remove the guide wire. NOTE: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.
4. Install the high mounted stop lamp (1) to the vehicle with the screws (2). Tighten Tighten the screws to 2 N.m (17 lb in).
5. Connect the electrical connector (4).
6. Install the headliner.
7. Install the left and right side rear window garnish molding.
8. Install the rear upper garnish molding. Refer to GARNISH MOLDING REPLACEMENT - REAR UPPER (AVALANCHE / ESCALADE EXT) or GARNISH MOLDING REPLACEMENT - REAR UPPER (TAHOE / YUKON / ESCALADE / SUBURBAN) in Interior Trim.

1. Raise the lift gate window.
2. Remove the retainers from the stop lamp.
3. Lower the lift gate window.
4. Raise the stop lamp to disconnect the electrical connector from the lamp.
5. Remove the center high-mounted stop lamp from the vehicle.

1. Connect the electrical harness to the stop lamp.
2. Install the center high-mounted stop lamp onto the vehicle.
3. Raise the lift gate window.
4. Install the retainers into the holes. NOTE: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems. Tighten Tighten the retainers to 1.2 N.m (10 lb in).
5. Close the lift gate window.

1. Ensure the headlamp switch is in the OFF position.
2. Remove the rear compartment cover assembly.
3. Remove the cargo box bridge center bar. Refer to PANEL REPLACEMENT - CARGO BOX BRIDGE CENTER (AVALANCHE) or PANEL REPLACEMENT - CARGO BOX BRIDGE CENTER (ESCALADE EXT) in Exterior Trim.
4. Remove the stop lamp retaining screws.
5. Disconnect the electrical connector (1).
6. Remove the stop lamp from the cargo box bridge center bar.

1. Install the stop lamp to the cargo box bridge center bar.
2. Connect the electrical connector (1).
3. Install the cargo box bridge center bar. Refer to PANEL REPLACEMENT - CARGO BOX BRIDGE CENTER (AVALANCHE) or PANEL REPLACEMENT - CARGO BOX BRIDGE CENTER (ESCALADE EXT) in Exterior Trim.
4. Inspect the operation.
5. Install the rear compartment cover assembly.

1. Ensure the headlamp switch is in the OFF position.
2. Remove the rear compartment cover assembly.
3. Remove the cargo box bridge center bar. Refer to PANEL REPLACEMENT - CARGO BOX BRIDGE CENTER (AVALANCHE) or PANEL REPLACEMENT - CARGO BOX BRIDGE CENTER (ESCALADE EXT) in Exterior Trim.
4. Remove the panel assembly from the vehicle.
5. Disconnect the electrical connector from the high mounted stop lamp. Refer to «HIGH MOUNTED STOP LAMP REPLACEMENT (UTILITY)»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-lights/#lighting-systems) or «HIGH MOUNTED STOP LAMP REPLACEMENT (CADILLAC)»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-lights/#lighting-systems) or «HIGH MOUNTED STOP LAMP REPLACEMENT (ESCALADE EXT)»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-lights/#lighting-systems) or «HIGH MOUNTED STOP LAMP REPLACEMENT (AVALANCHE)»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-lights/#lighting-systems) .

1. Install the stop lamp to the cargo box bridge center bar.
2. Connect the electrical connector.
3. Install the panel assembly to the vehicle.
4. Install the cargo box bridge center bar. Refer to PANEL REPLACEMENT - CARGO BOX BRIDGE CENTER (AVALANCHE) or PANEL REPLACEMENT - CARGO BOX BRIDGE CENTER (ESCALADE EXT) in Exterior Trim.
5. Inspect the operation.
6. Install the rear compartment cover assembly.

1. Ensure the headlamp switch is in the OFF position.
2. Remove the lens from the lamp assembly.
3. Remove the bulb.

1. Install the bulb.
2. Install the lens to the lamp assembly.
3. Inspect the operation.

1. Ensure that the headlamp switch is in the OFF position.
2. Open the endgate/liftgate.
3. Avalanche model shown. Remove the 2 screws retaining the tail/turn signal lamp assembly to the body.
4. Identify the bulb in need of replacement. The top bulb is a parking lamp and stop lamp The center bulb is a turn indicator lamp The lower bulb is a backup lamp
5. Rotate the bulb socket 1/4 turn counter-clockwise in order to remove the bulb sockets from the tail/turn lamp assembly.
6. Remove the bulbs from the sockets by pulling out the bulbs.

1. Install the bulb into the socket.
2. Install the bulb socket to the tail/turn lamp assembly by rotating the socket 1/4 turn clockwise.
3. Install the tail/turn signal lamp assembly to the vehicle with the 2 screws. NOTE: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems. Tighten Tighten the screws to 1.6 N.m (14 lb in).
4. Close the endgate/liftgate.
5. Inspect the operation.

Exterior Lamps

The exterior lighting system consist of the following lamps

1. The Headlamps
2. The Daytime Running Lamps (DRL)
3. Fog Lamps
4. The Park, Tail and Marker Lamps
5. Exterior Courtesy Lamps
6. The Turn Signal/Hazard Lamps
7. The Stop Lamps
8. The Backup Lamps
9. The Clearance Lamps

Headlamps

The headlamps may be turned on in two different ways. First, when the driver places the headlamp switch in the HEADLAMP position, for normal operation. Second, with the headlamp switch placed in the AUTO position, for automatic lamp control (ALC). During ALC the headlamps will be in day time running lamp (DRL) operation in daylight conditions, or headlamp operation in low light conditions.

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

If the headlight switch is left in the ON position, the inadvertent power control feature will turn off the headlights approximately 10 minutes after the ignition switch is turned to the OFF position. If the driver places the headlight switch in the ON position after the ignition switch has been turned OFF, or if the ignition switch is in the ACCY position, the headlights 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.

High Beams

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.

Low Beams (Except Escalade with High Intensity Discharge (HID))

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.

Low Beams (Escalade w/HID)

HID low beam headlamps are standard equipment on the Escalade. Normal operation of the HID system starts at the ballast. The headlamp ballast input connector receives battery positive voltage from the LH HID/EXP LP 20 A fuse and RH HID/EXP LP 20 A fuse in the underhood fuse block. When the low beam headlamps are requested the LOW HDLP relay supplies voltage to the ballast on the right headlamp low beam supply voltage circuit and the left headlamp low beam supply voltage circuit, which in turn begins the low beam operation as follows. Each ballast has a separate ground. As soon as the input power is applied, the ballast draws 20 amps from the battery for 5-10 seconds (depending on the input voltage level). The ballast is then able to charge the two outputs leading to the start to -360 volts and +800 volts. -360 volts and +800 volts are the voltages needed by the starter to strike, or start, the lamp. HID headlamps do not have filaments like traditional bulbs. Instead, the starter uses a high-voltage transformer to convert the +800 volts input power into 25,000 volts. The increased voltage is used in order to create an arc between the electrodes in the bulb. The creation of this arc begins the start up process.

Low Voltage Operation of HID Headlamps

The body control module (BCM) monitors the vehicle's system voltage while in the RUN power mode. When the system voltage drops below 8.9 volts, the following will occur

STAGE 1

If the low beam headlamps are ON, either manually or automatically, the BCM will turn ON the high beam headlamps by activating it's High Beam output.

STAGE 2

When the system voltage drops below 8.5 volts, the following will occur

1. If the low beam headlamps are currently ON, either manually or automatically, the BCM will turn OFF the low beam headlamps by deactivating it's Low Beam output.
2. If the headlamps are then turned ON manually, the manual switch redundancy will cause the low beam headlamps to remain on.

If during the same ignition cycle, the BCM enters either STAGE 1 or STAGE 2 operations noted above, and then determines that the system voltage has risen, the following will occur

1. If the BCM has entered STAGE 2 operation, it will not return to STAGE 1 operation until the system voltage rises above 9.4 volts.
2. If the BCM has entered STAGE 1 operation, it will not return to normal operation until the system voltage rises above 9.8 volts.

Electrical System Requirements with HID

Ensure that the battery and the harness are capable of supplying up to 20 amps of current per ballast, with less than 2 volts of system loss or voltage drop. Each ballast requires the 20 amps in order to ensure normal start-up and run up of the lamp. Run up is the term used to describe the extra power level given to the bulb from the -360 volt ballast output. The input current during the steady state operation is 3.4 amps at 12.8 volts.

Run Up Of The HID Lamp

After the lamp receives the strike from the starter and the arc is established, the ballast uses its -360 volt output in order to provide the run up power needed in order to keep the lamp on. The lamp rapidly increases in intensity from a dim glow to a very high-intensity, bright light called a steady state. Within 2 seconds of the arc being established in the bulb, 70% of steady state is complete. 100% of the steady state is completed within 30 seconds. A 75-watt power level is necessary in order to bring the lamp to a steady state in the required period of time.

When To Change The HID Bulb

Bulb failure occurs when the bulb gets older and becomes unstable. The bulb may begin shutting itself off sporadically and unpredictably at first, perhaps only once during a 24-hour period. When the bulb begins shutting itself off occasionally, the ballast will automatically turn the bulb back on again within 0.5 seconds. The ballast will re-strike the bulb so quickly that the bulb may not appear to have shut off. As the bulb ages, the bulb may begin to shut off more frequently, eventually over 30 times per minute. When the bulb begins to shut off more frequently, the ballast receives excessive, repetitive current input (20 amp). Repetitive and excessive restarts or re-strikes, without time for the ballast to cool down, will permanently damage the ballast. As a safeguard, when repetitive re-strikes are detected, the ballast will not attempt to re-strike the lamp. The ballast then shuts down and the bulb goes out.

The following symptoms are the noticeable signs of bulb failure

1. A flickering light, caused in the early stages of bulb failure
2. The lights go out, caused when the ballast detects excessive, repetitive bulb re-strike
3. Color change - the lamp may change to a dim pink glow

Input power to the ballast must be terminated in order to reset the ballast's fault circuitry. In order to terminate the input power to the ballast, turn the lights off and back on again. Turning the lights off and back on again resets all of the fault circuitry within the ballast until the next occurrence of excessive, repetitive bulb re-strikes. When excessive, repetitive bulb re-strikes occur, replace the starter/arc tube assembly. The ballast will begin the start-up process when the starter/arc tube assembly is replaced. Repeatedly resetting the input power can overheat the internal components and cause permanent damage to the ballast. Allow a few minutes of cool-down time in between reset attempts.

Bulb failures are often sporadic at first, and difficult to repeat. Technicians can identify bulb failure by observing if the problem gets progressively worse over the next 100 hours of operation.

Light Color (w/HID)

White light has a different color rating than regular headlamps. The range of white light that is acceptable is broad when compared to halogens. Therefore, some variation in headlight coloring between the right and left headlamp will be normal. One HID at the end of the normal range may appear considerably different in color from one at the other end of the range. Difference in color is normal. Replace the arc tube only if the arc tube is determined to be at the bulb failure stage.

Daytime Running Lamps (DRL)

The 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. 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 headlights will cancel the daytime running lamps operation. The DRL can be manually turned OFF by depressing the AHL/DRL 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 and turns ON the DRL OFF lamp in the headlamp switch by grounding the DRL OFF indicator control circuit. 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 headlight 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, the DRL receive voltage on the DRL supply voltage circuit. Ground for the DRL is at G100.

Fog Lamps

With both the ignition switch in the [RUN] position, and the park lamps ON, the fog lights will illuminate when the driver depresses the fog lamp switch. The FOG LPS 15 A fuse in the underhood fuse block supplies battery positive voltage to the fog lamp relay switch and coil. With the headlamp switch in either the park or headlamp position, and the fog lamp switch is in the ON position, the body control module (BCM) will energize the fog lamp relay control circuit. The BCM receives the park lamp ON signal from the interior park lamps supply voltage signal circuit. The current flow is from the fog lamp relay to both front fog lamps and to ground G100. The state of the fog lamps will remain the same until the fog lamp switch position is changed, or the ignition switch is cycled OFF and ON. Fog lamp operation will be cancelled whenever the park lamps, are turned OFF or the high beam headlights have been selected.

The rear fog lamps are controlled in much the same way, however the front fog lamps must be on in order to turn on the rear fog lamps. The SEO 1 15 A fuse in the underhood fuse block supplies battery positive voltage to the rear fog lamp relay switch and coil. Both the relay control and current flow are the same as the front fog lamps with the exception of the rear fog lamp ground at G402.

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 HEAD position or anytime the headlights 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 headlight 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 headlight 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.

Exterior Courtesy Lamps

The BCM, drivers door module (DDM), and the passenger door module (PDM) communicate through the class 2 serial data system. The DDM and the PDM supply power and ground to the left and right exterior lamps respectively. When the BCM commands illuminated entry, a command is also sent to the DDM/PDM for illumination of the exterior courtesy lamps. If the door locks are activated to the LOCK position, or if the ignition switch is turned to either the ON or RUN position the exterior courtesy lamps will deactivate immediately.

When an outside door handle is lifted or a door is opened, the exterior courtesy lamps illuminate.

Turn Signal/Hazard 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, a voltage signal is completed from the turn signal switch to the turn sign/flasher module. When the hazard flasher switch is activated, a ground signal is completed from the turn signal/hazard 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 10 A fuses in the I/P fuse block to the appropriate turn signal or to all 4 fuses for hazard operation. The instrument panel cluster (IPC) indicators receive voltage from the LT TURN and RT TURN fuses as well as the DDM/PDM for the mirror turn signals.

The DDM/PDM has no function or control of the mirror turn signals other that a pass through connection for the circuits. 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 I PC turn indicators. The front turn signals are grounded at G100. The rear turn signals are grounded at G401. The Mirror turn signals are grounded by the DDM/PDM.

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 I/P fuse block, and to the turn signal/hazard module. 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 cruise control.

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 HEAD 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.

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.

Interior Lamps

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

1. Courtesy/Illuminated entry lamps
2. Dome lamps
3. I/P compartment lamp
4. Map lamps
5. Reading lamps
6. 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. When the driver places the dome lamp defeat switch in the OFF position, the courtesy/illuminated entry lamps will be disabled. 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.

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. Voltage for the courtesy lamp supply voltage circuit and the 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. 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, 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 courtesy lamps supply voltage circuit of the 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. Ground is provided to the vanity lamps at G203.

I/P Compartment Lamp

The inadvertent power courtesy lamps supply voltage circuit of the BCM provides battery positive voltage to the instrument panel compartment lamp. When the I/P compartment is opened, a switch closes to provide a ground circuit and the I/P compartment lamp illuminates. Ground is provided to the I/P compartment lamp at G203.

Reading Lamps

The inadvertent power courtesy lamps supply voltage circuit of the 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. Ground is provided to the reading lamps at G203.

Battery Rundown Protection/Inadvertent Power

The BCM inadvertent power courtesy lamps supply voltage circuit provides battery positive voltage to all of the interior reading lamps, I/P compartment lamp, underhood 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 20 minutes with the ignition switch in the OFF position, the BCM wilt deactivate the inadvertent power courtesy lamps supply voltage circuit to prevent a total battery discharge condition. Only when the ignition switch is cycled back to the RUN position will the BCM reset the internal timer and reactivate the inadvertent power courtesy lamps supply voltage circuit.

The BCM also utilizes the inadvertent power courtesy lamps supply voltage circuit as a courtesy 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 courtesy lamps 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 vacuum fluorescent (VF) displays turn on at maximum brightness. When the park lamps are on, all incandescent back lighting turn on at the dimming level indicated by the I/P dimmer switch. At the same time all vacuum fluorescent (VF) displays dim to match the indicated dimming level. The panel dimmer switch potentiometer is an input to the 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 vacuum fluorescent (VF) displays, as well as all incandescent back lighting respond from minimum intensity to maximum brightness in response to the I/P dimmer switch.

1. The instrument panel cluster (IPC)
2. Radio
3. Window and heated seat switches
4. Garage door opener switch
5. Sunroof switch
6. HVAC control assembly
7. Headlamp and panel dimmer switch
8. Tow/haul switch
9. Transfer case shift control switch
10. Height control switch
11. PSIR disable switch
12. PRNDL lamps
13. Traction control switch
14. Steering wheel control switches
15. Rear wiper/washer switch

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

The I\P cluster illumination lamps receive voltage and are controlled by 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 BCU on the instrument panel lamps dimming control circuit. Ground for the traction control switch , steering wheel controls, and the rear window/wiper switch is at G108. Ground for the remaining switches is at G203.

1. Traction control switch traction control OFF indicator
2. Height control switch high clearance indicator
3. Transfer case control switch 4WD position indicator
4. Headlamp and panel dimmer switch DRL OFF indicator

The indicators receive voltage from the BCM on the LED dimming circuit. Ground/control for the indicators is from the various modules. Voltage for the LED dimming supply circuit, instrument panel lamps dimming control circuit and the instrument panel lamps dimming supply circuit is from the TBC A fuse in the instrument panel fuse block directly through the BCM to these circuits. A short to ground on only the instrument panel lamps dimming control circuit will open the fuse. The modules controlling the above indicators are as follows

1. Electronic brake control module (EBCM)
2. Electronic suspension control module
3. Transfer case shift control module
4. Body control module (BCM)

Scheme 264

See also:
• DIAGNOSTIC SYSTEM CHECK - LIGHTING SYSTEMS
• FOG LAMP AIMING PROCEDURE