Lighting Systems Chevrolet Cutaway G3500

Fastener Tightening Specifications

Fastener Tightening Specifications

Headlights Schematics

For headlights schematics refer to appropriate System Wiring Diagrams article.

Exterior Lights Schematics

For exterior lights schematics refer to appropriate System Wiring Diagrams article.

Interior Lights Schematics

For interior lights schematics refer to appropriate System Wiring Diagrams article.

Interior Lights Dimming Schematics

For interior lights dimming schematics refer to appropriate System Wiring Diagrams article.

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Backup Lamp - Left (Passenger/Cargo) Connector End Connector Part Information 12160393 2-Way Lamp Socket Wedge Base W3 Right Angle (L-GY) Pin Wire Color Circuit No. Function A L-GN 24 Backup Lamp Supply Voltage G BK 850 Ground

Backup Lamp - Right (Passenger/Cargo) Connector End Connector Part Information 12160393 2-Way Lamp Socket Wedge Base W3 Right Angle (L-GY) Pin Wire Color Circuit No. Function A L-GN 24 Backup Lamp Supply Voltage G BK 1050 Ground

Center High Mounted Stop Lamp (CHMSL) (Passenger/Cargo) Connector End Connector Part Information 12047663 2-Way M Metri-Pack 150 Series (BK) Pin Wire Color Circuit No. Function A L-BU 1320 CHMSL Supply Voltage B BK 850 Ground

Courtesy/Reading Lamp - Front Connector End Connector Part Information 12047781 3-Way F Metri-Pack 150 Series (BK) Pin Wire Color Circuit No. Function A D-BU/WH 149 Courtesy Lamp Supply Voltage B BK 450 Ground C OG 1732 Inadvertent Power Supply Voltage

Courtesy/Reading Lamp - Mid (Passenger/Cargo) Connector End Connector Part Information 12047781 3-Way F Metri-Pack 150 Series (BK) Pin Wire Color Circuit No. Function A D-BU/WH 149 Courtesy Lamp Supply Voltage B BK 450 Ground C OG 1732 Inadvertent Power Supply Voltage

Courtesy/Reading Lamp - Rear (Passenger/Cargo) Connector End Connector Part Information 12047781 3-Way F Metri-Pack 150 Series (BK) Pin Wire Color Circuit No. Function A D-BU/WH 149 Courtesy Lamp Supply Voltage B BK 450 Ground C OG 1732 Inadvertent Power Supply Voltage

Dome Fluorescent Work Lamps (PNP w/UF2) Connector End Connector Part Information 12052832 2-Way F Metri-Pack 150 Series (BK) Pin Wire Color Circuit No. Function A OG 840 Battery Positive Voltage B BK 150 Ground

Dome Lamp - Rear (Cargo) Connector End Connector Part Information 15528758 2-Way F Dome Lamp Base (NA) Pin Wire Color Circuit No. Function A D-BU/WH 149 Courtesy Lamp Supply Voltage B BK 850 Ground

Door Jamb Switch - LR Side (E26) Connector End Connector Part Information 12059251 2-Way F Metri-Pack 150 Series (RD) Pin Wire Color Circuit No. Function A BK 450 Ground B YE/BK 1181 Rear Door Open Switch Signal

Door Jamb Switch - RR Side (Passenger/Cargo) Connector End Connector Part Information 12059251 2-Way F Metri-Pack 150 Series (RD) Pin Wire Color Circuit No. Function A BK 450 Ground B YE/BK 1181 Rear Door Open Switch Signal

Door Latch Assembly - Cargo - C1 Connector End Connector Part Information 15354716 4-Way F GT 150 Sealed 3.2 X 4.0 (BK) Pin Wire Color Circuit No. Function A L-GN 1177 Door Open Switch Signal B-C - - Not Used D BK 1050 Ground

Door Latch Assembly - Driver - C1 Connector End Connector Part Information 15354716 4-Way F GT 150 Sealed 3.2 X 4.0 (BK) Pin Wire Color Circuit No. Function A TN 126 Left Front Door Open Switch Signal B-C - - Not Used D BK 450 Ground

Door Latch Assembly - Passenger - C1 Connector End Connector Part Information 15354716 4-Way F GT 150 Sealed 3.2 X 4.0 (BK) Pin Wire Color Circuit No. Function A BK 450 Ground B-C - - Not Used D L-GN 1177 Door Open Switch Signal

Headlamp - High Beam - Left (Composite) Connector End Connector Part Information 12059183 2-Way F Metri-Pack 280 Series- Sealed (BK) Pin Wire Color Circuit No. Function A D-GN/WH 711 Left Headlamp High Beam Supply Voltage B BK 250 Ground

Headlamp - High Beam - Right (Composite) Connector End Connector Part Information 12059183 2-Way F Metri-Pack 280 Series- Sealed (BK) Pin Wire Color Circuit No. Function A L-GN/BK 311 Right Headlamp High Beam Supply Voltage B BK 650 Ground

Headlamp - Left (Sealed) Connector End Connector Part Information 12034372 3-Way F Metri-Pack 800 Series (BK) Pin Wire Color Circuit No. Function A BK 250 Ground B D-GN/WH 711 Left Headlamp High Beam Supply Voltage C YE 712 Left Headlamp Low Beam Supply Voltage

Headlamp - Low Beam - Left (Composite) Connector End Connector Part Information 12059181 2-Way F Metri-Pack 280 Series Sealed (GY) Pin Wire Color Circuit No. Function A YE 712 Left Headlamp Low Beam Supply Voltage B BK 250 Ground

Headlamp - Low Beam - Right (Composite) Connector End Connector Part Information 12059181 2-Way F Metri-Pack 280 Series Sealed (GY) Pin Wire Color Circuit No. Function A TN/WH 312 Right Headlamp Low Beam Supply Voltage B BK 650 Ground

Headlamp - Right (Sealed) Connector End Connector Part Information 12034372 3-Way F Metri-Pack 800 Series (BK) Pin Wire Color Circuit No. Function A BK 650 Ground B L-GN/BK 311 Right Headlamp High Beam Supply Voltage C TN/WH 312 Right Headlamp Low Beam Supply Voltage

Headlamp and Panel Dimmer Switch - C1 Connector End Connector Part Information 15332161 12-Way F GT 150 (BK) Pin Wire Color Circuit No. Function A GY 705 5-Volt Reference B BN/WH 230 Instrument Panel Lamps Dimming Control C BK 350 Ground D WH 103 Headlamp Switch Headlamps On Signal E BN/WH 301 Park Lamp Switch On Signal F D-GN 306 DRL On/Off Signal G OG/BK 2090 Dimming Input H GY/BK 2226 Dimming Return J D-BU/WH 1495 Courtesy Lamps On Signal K PU/WH 1382 LED Dimming Signal L PK 1348 Headlamp On Indicator Supply Voltage M PU 328 Interior Lamp Defeat Switch Signal

License Lamp (Passenger/Cargo) Connector End Connector Part Information 12110053 2-Way F Wedge Base- Type W-2 Sealed (GY) Pin Wire Color Circuit No. Function A BN 2509 Left Rear Park Lamps Supply Voltage B BK 1050 Ground

Marker Lamp - LF Connector End Connector Part Information 15300027 2-Way F Metri-Pack 280 Series- Sealed (BK) Pin Wire Color Circuit No. Function A BN 2309 Front Park Lamps Supply Voltage B BK 250 Ground

Marker Lamp - RF Connector End Connector Part Information 15300027 2-Way F Metri-Pack 280 Series- Sealed (BK) Pin Wire Color Circuit No. Function A BN 2309 Front Park Lamps Supply Voltage B BK 650 Ground

Park/Turn Signal Lamp - LF Connector End Connector Part Information 12040977 3-Way F M/P 280 Sealed (BK) Pin Wire Color Circuit No. Function A L-BU 2114 Left Front Turn Signal Lamps Supply Voltage B BN 2309 Front Park Lamps Supply Voltage C BK 250 Ground

Park/Turn Signal Lamp - RF Connector End Connector Part Information 12040977 3-Way F M/P 280 Sealed (BK) Pin Wire Color Circuit No. Function A D-BU 2115 Right Front Turn Signal Lamps Supply Voltage B BN 2309 Front Park Lamps Supply Voltage C BK 650 Ground

Stop Lamp Switch Connector End Connector Part Information 12040551 6-Way F Metri-Pack 480 Series (BK) Pin Wire Color Circuit No. Function A WH 17 Stop Lamp Switch Signal B RD/WH 1540 Battery Positive Voltage C PK 739 Ignition 1 Voltage D PU 420 TCC Brake Switch/Cruise Control Release Signal E L-GN/BK 584 A/T Shift Lock Control Switch Supply Voltage F D-GN/WH 1135 A/T Shift Lock Control Solenoid Supply Voltage

Tail/Stop and Turn Signal Lamp - Left (Passenger/Cargo) Connector End Connector Part Information 12160394 3-Way Lamp Socket Wedge Base W3 Right Angle (WH) Pin Wire Color Circuit No. Function A YE 618 Left Rear Turn Signal Lamp Supply Voltage B BN 2509 Left Rear Park Lamps Supply Voltage G BK 850 Ground BK 850 Ground

Tail/Stop and Turn Signal Lamp - Right (Passenger/Cargo) Connector End Connector Part Information 12160394 3-Way Lamp Socket Wedge Base W3 Right Angle (WH) Pin Wire Color Circuit No. Function A YE 619 Right Rear Turn Signal Lamp Supply Voltage B BN 2609 Right Rear Park Lamps Supply Voltage G BK 1050 Ground BK 1050 Ground

Trailer Stop/Turn Relay - Left (UY7) Connector End Connector Part Information 12129716 4-Way F Metri-Pack 280 Series Flexlock (GY) Pin Wire Color Circuit No. Function 30 OG 1340 Battery Positive Voltage 85 YE 618 Left Rear Turn Signal Lamp Supply Voltage 86 BK 150 Ground 87 YE 1618 Trailer Left Rear Turn/Stop Lamp Supply Voltage

Trailer Stop/Turn Relay - Right (UY7) Connector End Connector Part Information 12129716 4-Way F Metri-Pack 280 Series Flexlock (GY) Pin Wire Color Circuit No. Function 30 OG 1340 Battery Positive Voltage 85 D-GN 619 Right Rear Turn Signal Lamp Supply Voltage 86 BK 150 Ground 87 D-GN 1619 Trailer Right Rear Turn/Stop Lamp Supply Voltage

Turn Signal/Hazard Flasher Module Connector End Connector Part Information 15332177 16-Way F GT 150 (BK) Pin Wire Color Circuit No. Function A D-BU 5364 Left DRL/Turn Supply Voltage B YE 18 Left Rear Stop/Turn Lamp Supply Voltage C L-GN/BK 592 DRL Low Control D D-GN 19 Right Rear Stop/Turn Lamp Supply Voltage E D-GN 5365 Right DRL/Turn Supply Voltage F WH 17 Stop Lamp Switch Signal G L-BU/WH 1314 Left Front Turn Signal Lamp Supply Voltage H D-BU/WH 1315 Right Front Turn Signal Lamp Supply Voltage J RD/WH 540 Battery Positive Voltage K WH 111 Hazard Switch Signal L L-BU/WH 1414 Left Turn Signal Switch Signal M D-BU/WH 1415 Right Turn Signal Switch Signal N BK 350 Ground P-S - - Not Used

Turn Signal/Multifunction Switch - C1 Connector End Connector Part Information 12064862 8-Way F Metri-Pack 150 Series (BK) Pin Wire Color Circuit No. Function A D-BU/WH 1415 Right Turn Signal Switch Signal B PK 739 Ignition 1 Voltage C L-BU/WH 1414 Left Turn Signal Switch Signal D-F - - Not Used G TN 28 Horn Relay Control H WH 111 Hazard Switch Signal

Turn Signal/Multifunction Switch - C2 Connector End Connector Part Information 12059800 5-Way F Metri-Pack 150 Series (BK) Pin Wire Color Circuit No. Function A YE 307 Headlamp Switch Flash to Pass Signal B L-GN 11 Headlamp Dimmer Switch Signal C-D - - Not Used E BK 350 Ground

Turn Signal/Multifunction Switch - C3 Connector End Connector Part Information 15339058 7-Way F Metri-Pack/150 Series (GY) Pin Wire Color Circuit No. Function G - - Not Used H PK 94 Windshield Washer Switch Signal J GY 478 Windshield Wiper Switch Signal 2 K D-BU 477 Windshield Wiper Switch Signal 1 L-N - - Not Used

Turn Signal/Multifunction Switch - C4 (K34) Connector End Connector Part Information 12047786 4-Way M Metri-Pack 150 Series (BK) Pin Wire Color Circuit No. Function A PK 739 Ignition 1 Voltage B GY 397 Cruise Control On Switch Signal C GY/BK 87 Cruise Control Resume/Accel Switch Signal D D-BU 84 Cruise Control Set/Coast Switch Signal

Underhood Lamp Connector End Connector Part Information 12052644 2-Way F Metri-Pack 150 Series- Sealed (GY) Pin Wire Color Circuit No. Function A OG 1732 Inadvertent Power Supply Voltage B BK 1250 Ground

Vanity Mirror Lamp - Left (DH6) Connector End Connector Part Information 12047663 2-Way M Metri-Pack 150 Series (BK) Pin Wire Color Circuit No. Function A OG 1732 Inadvertent Power Supply Voltage B BK 450 Ground

Vanity Mirror Lamp - Right (DH6) Connector End Connector Part Information 12047663 2-Way M Metri-Pack 150 Series (BK) Pin Wire Color Circuit No. Function A OG 1732 Inadvertent Power Supply Voltage B BK 450 Ground

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.

Diagnostic System Check - Lighting Systems

Scan Tool Output Controls

Body Control Module (BCM) Scan Tool Output Controls

Scan Tool Data List

Body Control Module (BCM) Scan Tool Data List

Instrument Panel Cluster (IPC) Module Scan Tool Data List

Diagnostic Trouble Code (DTC) List

Diagnostic Trouble Code (DTC) List

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 backlight lamps control circuits is from the TBC 3 fuse 16 in the underhood 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 backlight lamps control circuit is shorted to ground.
4. The instrument panel lamps dimming control circuit is shorted to ground.
5. There is a loss of the underhood fuse block TBC 3 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 Conditions and Poor Connections»(/chevrolet/cutaway-g3500/1997-2012/remont/body-electrical/#wiring-systems-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor) in Wiring Systems.
2. A short to ground in the following circuits will cause the TBC 3 fuse to open. The backlight lamps control. The instrument panel lamps dimming control. The LED dimming signal. Battery positive voltage from the underhood fuse block TBC 3 fuse.
3. An open in the TBC 3 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 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.

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.

DTC B0951

The body control module (BCM) supplies battery positive voltage to the reading lamps, underhood lamp, instrument panel (I/P) compartment lamp, and both visor vanity mirror lamps. In the event that any of these lamps were to remain illuminated for 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 4 fuse 11 in the underhood 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 to the reading lamps, underhood lamp, I/P compartment lamp, and both visor vanity mirror lamps is shorted to ground for more than 1 second.
2. There is a loss of the instrument panel fuse block TBC 4 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 reading lamps, underhood lamp, I/P compartment lamp, and both visor vanity mirror 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 Conditions and Poor Connections»(/chevrolet/cutaway-g3500/1997-2012/remont/body-electrical/#wiring-systems-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor) 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 4 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.

DTC B1480

When the body control module (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 low beam headlamp relay control circuit is open or shorted to ground.
2. When the BCM receives a low beam headlamp ON command and the low beam headlamp relay control circuit is shorted to voltage.
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.

DTC B2575

When the body control module (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 high beam headlamp relay control circuit is open or 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.
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.

DTC B2580

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.

DTC B2585

The body control module (BCM) signals the turn/hazard flasher module to illuminate the daytime running lamps (DRL) by grounding the DRL low control circuit. The DRL operates when the ignition switch is in the RUN position and 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 and the DRL low control circuit is shorted to ground.
2. When the BCM sends a DRL ON command and the DRL low control circuit is shorted to voltage or open.
3. When the Flasher fuse 15 in the underhood fuse block is open.
4. When the following circuits are shorted to ground: Left rear stop/turn lamp supply voltage Right rear stop/turn lamp supply voltage Left DRL/turn supply voltage Right DRL/turn supply voltage Left turn signal indicator lamp supply voltage Right turn signal indicator lamp supply voltage Battery supply voltage from the underhood fuse block Flasher fuse
5. The instrument panel lamps dimming control circuit is shorted to ground.

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.

1. Perform a visual inspection for loose or poor connections at all related components. Refer to «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/cutaway-g3500/1997-2012/remont/body-electrical/#wiring-systems-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor) in Wiring Systems.
2. A short to ground in the following circuits will cause the Flasher fuse to open. Left rear stop/turn lamp supply voltage Right rear stop/turn lamp supply voltage Left DRL/turn supply voltage Right DRL/turn supply voltage Left turn signal indicator lamp supply voltage Right turn signal indicator lamp supply voltage Battery supply voltage from the underhood fuse block Flasher fuse
3. An open in the Flasher fuse will cause the DRL, turn signals and the hazard flashers to be inoperative.

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

1. 2: This step test determines if the problem exists in the DRL control/BCM or other circuitry.
2. 3: This step test determines if the problem exists in the wiring or the BCM.
3. 7: This step test determines if the problem exists in the wiring or the BCM.
4. 9: After replacement of the BCM you must calibrate the new module for proper operation.

DTC B2600

The body control module (BCM) receives a variable voltage signal from the instrument panel (I/P) dimmer switch requesting to illuminate the instrument panel controls 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 backlight lamps control circuit, instrument panel lamps dimming control circuit, and the LED dimming signal circuit.

Voltage for the backlight lamps control circuit, instrument panel lamps dimming control circuit, and the LED dimming signal circuits is from the TBC 3 fuse 16 in the underhood fuse block directly through the BCM to these circuits.

The battery voltage must be between 9.0-16.0 volts.

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

The instrument panel illumination lamps and the controls 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 Conditions and Poor Connections»(/chevrolet/cutaway-g3500/1997-2012/remont/body-electrical/#wiring-systems-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor) in Wiring Systems.
2. A short to ground in the following circuits will cause the TBC 3 fuse to open. The backlight lamps control. The instrument panel lamps dimming control. The LED dimming signal. Battery positive voltage from the underhood fuse block TBC 3 fuse.
3. An open in the TBC 3 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.

DTC B2610

The body control module (BCM) receives a ground signal from the door jamb, or courtesy lamp switch 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 body fuse block TBC 2 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 before the first connection after the BCM or shorted to voltage.
3. There is a loss of the body fuse block TBC 2 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 Conditions and Poor Connections»(/chevrolet/cutaway-g3500/1997-2012/remont/body-electrical/#wiring-systems-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor) in Wiring Systems.
2. An open circuit up to the first splice only in the courtesy lamp supply voltage circuit from the BCM, will set the DTC.
3. A short to ground in the following circuits will cause the TBC 2 fuse to open. Courtesy lamp supply voltage. Backup lamp supply voltage. Battery positive voltage from the body fuse block TBC 2 fuse.

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

1. 2: This step test determines if the problem is a short to ground in the wiring.
2. 3: This step test determines if the problem exists in the wiring or the BCM.
3. 4: This step test determines if the problem exists in the wiring or the BCM.
4. 6: After replacement of the BCM you must calibrate the new module for proper operation.

DTC B2615 (Without YF7)

The body control module (BCM) receives a ground signal from the door jamb or courtesy lamp switches requesting courtesy/dome lamp illumination. When this occurs, the BCM sends a voltage through the courtesy lamp high control circuit to the courtesy lamp relay, illuminating the courtesy/dome lamps.

Voltage for the courtesy lamp high control circuit as well as the backup lamp supply voltage circuit is from the body fuse block TBC 2 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 high control circuit is shorted to ground.
2. When the BCM is not receiving a courtesy lamp illumination request signal and the courtesy lamp high control circuit is open or shorted to voltage.
3. When the courtesy lamp relay coil side is open.
4. There is a loss of the body fuse block TBC 2 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 Conditions and Poor Connections»(/chevrolet/cutaway-g3500/1997-2012/remont/body-electrical/#wiring-systems-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor) in Wiring Systems.
2. A short to ground in the following circuits will cause the TBC 2 fuse to open. Courtesy lamp high control. Backup lamp supply voltage. Battery positive voltage from the body fuse block TBC 2 fuse.

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

1. 5: This step tests for an open coil in the courtesy lamp relay.
2. 8: After replacement of the BCM you must calibrate the new module for proper operation.

DTC B2615 (With YF7)

The body control module (BCM) directly sends a 5 volt reference voltage to the instrument panel (I/P) dimmer switch which is then adjusted based on the I/P dimmer switch position and returned as a low reference and a signal 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. When the BCM monitors a 5 volt reference circuit voltage of less than 4.5 volts.
2. When the BCM monitors a 5 volt reference circuit voltage of greater than 5.5 volts.
3. When the BCM monitors a signal 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 low reference circuit.

DTC B2620

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 signal circuit, instrument panel lamps dimming control circuit, and the backlight lamps control circuit.

Voltage for the LED dimming signal circuit, instrument panel lamps dimming control circuit, and the backlight lamps control circuit is from the TBC 3 fuse 16 in the underhood fuse block directly through the BCM to these circuits.

The battery voltage must be between 9.0-16.0 volts.

1. The backlight lamps control circuit is shorted to ground.
2. The instrument panel lamps dimming control circuit is shorted to ground.
3. The LED dimming signal circuit is shorted to ground.
4. There is a loss of the underhood fuse block TBC 3 battery supply voltage to the BCM for 1 second.

The dimming 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. Perform a visual inspection for loose or poor connections at all related components. Refer to «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/cutaway-g3500/1997-2012/remont/body-electrical/#wiring-systems-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor) in Wiring Systems.
2. A short to ground in the following circuits will cause the TBC 3 fuse to open. The backlight lamps control. The instrument panel lamps dimming control. The LED dimming signal. Battery positive voltage from the underhood fuse block TBC 3 fuse.
3. An open in the TBC 3 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.

DTC B2625

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 Conditions and Poor Connections»(/chevrolet/cutaway-g3500/1997-2012/remont/body-electrical/#wiring-systems-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor) in Wiring Systems.

DTC B3801

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.

DTC B3802

1. Perform the «Diagnostic System Check - Lighting Systems»(/chevrolet/cutaway-g3500/1997-2012/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»(/chevrolet/cutaway-g3500/1997-2012/remont/exterior-lights/#lighting-systems) «Interior Lighting Systems Description and Operation»(/chevrolet/cutaway-g3500/1997-2012/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»(/chevrolet/cutaway-g3500/1997-2012/remont/body-electrical/#wiring-systems-diagnostic-information-and-procedures__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 Conditions 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»(/chevrolet/cutaway-g3500/1997-2012/remont/exterior-lights/#lighting-systems__backup-lamps-always-on)
2. «Backup Lamps Inoperative»(/chevrolet/cutaway-g3500/1997-2012/remont/exterior-lights/#lighting-systems__backup-lamps-inoperative)
3. «Courtesy Lamps Always On»(/chevrolet/cutaway-g3500/1997-2012/remont/exterior-lights/#lighting-systems__courtesy-lamps-always-on)
4. «Courtesy Lamps Inoperative (Lamps)»(/chevrolet/cutaway-g3500/1997-2012/remont/exterior-lights/#lighting-systems__courtesy-lamps-inoperative-lamps) or «Courtesy Lamps Inoperative (Defeat Switch)»(/chevrolet/cutaway-g3500/1997-2012/remont/exterior-lights/#lighting-systems__courtesy-lamps-inoperative-defeat-switch)
5. «Daytime Running Lamps (DRL) Inoperative (Lamps)»(/chevrolet/cutaway-g3500/1997-2012/remont/exterior-lights/#lighting-systems__daytime-running-lamps-drl-inoperative-lamps) or «Daytime Running Lamps (DRL) Inoperative (Defeat Switch)»(/chevrolet/cutaway-g3500/1997-2012/remont/exterior-lights/#lighting-systems__daytime-running-lamps-drl-inoperative-defeat)
6. «Dome Lamps Always On»(/chevrolet/cutaway-g3500/1997-2012/remont/exterior-lights/#lighting-systems__dome-lamps-always-on)
7. «Dome Lamps Inoperative»(/chevrolet/cutaway-g3500/1997-2012/remont/exterior-lights/#lighting-systems__dome-lamps-inoperative)
8. «Hazard Lamps Always On»(/chevrolet/cutaway-g3500/1997-2012/remont/exterior-lights/#lighting-systems__hazard-lamps-always-on)
9. «Hazard Lamps Inoperative»(/chevrolet/cutaway-g3500/1997-2012/remont/exterior-lights/#lighting-systems__hazard-lamps-inoperative)
10. «Headlamps Always On - Low or High Beam»(/chevrolet/cutaway-g3500/1997-2012/remont/exterior-lights/#lighting-systems__headlamps-always-on-low-or)
11. «Headlamps Inoperative - High Beams»(/chevrolet/cutaway-g3500/1997-2012/remont/exterior-lights/#lighting-systems__headlamps-inoperative-high-beams)
12. «Headlamps Inoperative - Low Beams»(/chevrolet/cutaway-g3500/1997-2012/remont/exterior-lights/#lighting-systems__headlamps-inoperative-low-beams)
13. «Headlamps Inoperative - Low and High Beams»(/chevrolet/cutaway-g3500/1997-2012/remont/exterior-lights/#lighting-systems__headlamps-inoperative-low-and-high)
14. «Headlamps Inoperative - Flash to Pass»(/chevrolet/cutaway-g3500/1997-2012/remont/exterior-lights/#lighting-systems__headlamps-inoperative-flash-to-pass)
15. «High Beam Indicator Always On»(/chevrolet/cutaway-g3500/1997-2012/remont/exterior-lights/#lighting-systems__high-beam-indicator-always-on)
16. «High Beam Indicator Inoperative»(/chevrolet/cutaway-g3500/1997-2012/remont/exterior-lights/#lighting-systems__high-beam-indicator-inoperative)
17. «Interior Backlighting Does Not Dim»(/chevrolet/cutaway-g3500/1997-2012/remont/exterior-lights/#lighting-systems__interior-backlighting-does-not-dim)
18. «Interior Backlighting Inoperative»(/chevrolet/cutaway-g3500/1997-2012/remont/exterior-lights/#lighting-systems__interior-backlighting-inoperative)
19. «Park, License, and Tail Lamps Always On»(/chevrolet/cutaway-g3500/1997-2012/remont/exterior-lights/#lighting-systems__park-license-and-tail-lamps-always)
20. «Park, License, and Tail Lamps Inoperative»(/chevrolet/cutaway-g3500/1997-2012/remont/exterior-lights/#lighting-systems__park-license-and-tail-lamps-inoperative)
21. «Reading Lamp(s) Inoperative»(/chevrolet/cutaway-g3500/1997-2012/remont/exterior-lights/#lighting-systems__reading-lamps-inoperative)
22. «Stop Lamps Always On»(/chevrolet/cutaway-g3500/1997-2012/remont/exterior-lights/#lighting-systems__stop-lamps-always-on)
23. «Stop Lamps Inoperative»(/chevrolet/cutaway-g3500/1997-2012/remont/exterior-lights/#lighting-systems__stop-lamps-inoperative)
24. «Turn Signal Lamps and/or Indicators Always On or Flashing»(/chevrolet/cutaway-g3500/1997-2012/remont/exterior-lights/#lighting-systems__turn-signal-lamps-andor-indicators-always)
25. «Turn Signal Lamps and/or Indicators Inoperative»(/chevrolet/cutaway-g3500/1997-2012/remont/exterior-lights/#lighting-systems__turn-signal-lamps-andor-indicators-inoperative)
26. «Underhood Lamp Inoperative»(/chevrolet/cutaway-g3500/1997-2012/remont/exterior-lights/#lighting-systems__underhood-lamp-inoperative)
27. «Vanity Mirror Lamp(s) Inoperative»(/chevrolet/cutaway-g3500/1997-2012/remont/exterior-lights/#lighting-systems__vanity-mirror-lamps-inoperative)

Backup Lamps Always On

Backup Lamps Always On

Backup Lamps Inoperative

Backup Lamps Inoperative

Courtesy Lamps Always On

Courtesy Lamps Always On

Courtesy Lamps Inoperative (Lamps)

Courtesy Lamps Inoperative (Lamps)

Courtesy Lamps Inoperative (Defeat Switch)

Courtesy Lamps Inoperative (Defeat Switch)

Daytime Running Lamps (DRL) Inoperative (Lamps)

Daytime Running Lamps (DRL) Inoperative (Lamps)

Daytime Running Lamps (DRL) Inoperative (Defeat Switch)

Daytime Running Lamps (DRL) Inoperative (Defeat Switch)

Dome Lamps Always On

Dome Lamps Always On

Dome Lamps Inoperative

Dome Lamps Inoperative

Hazard Lamps Always On

Hazard Lamps Always On

Hazard Lamps Inoperative

Hazard Lamps Inoperative

Headlamps Always On - Low or High Beam

Headlamps Always On - Low or High Beam

Headlamps Inoperative - High Beams

Headlamps Inoperative - High Beams

Headlamps Inoperative - Low Beams

Headlamps Inoperative - Low Beams

Headlamps Inoperative - Low and High Beams

Headlamps Inoperative - Low and High Beams

Headlamps Inoperative - Flash to Pass

Headlamps Inoperative - Flash to Pass

High Beam Indicator Always On

High Beam Indicator Always On

High Beam Indicator Inoperative

High Beam Indicator Inoperative

Interior Backlighting Does Not Dim

Interior Backlighting Does Not Dim

Interior Backlighting Inoperative

Interior Backlighting Inoperative

Park, License, and Tail Lamps Always On

Park, License, and Tail Lamps Always On

Park, License, and Tail Lamps Inoperative

Park, License, and Tail Lamps Inoperative

Reading Lamp(s) Inoperative

Reading Lamp(s) Inoperative

Stop Lamps Always On

Stop Lamps Always On

Stop Lamps Inoperative

Stop Lamps Inoperative

Turn Signal Lamps and/or Indicators Always On or Flashing

Turn Signal Lamps and/or Indicators Always On or Flashing

Turn Signal Lamps and/or Indicators Inoperative

Turn Signal Lamps and/or Indicators Inoperative

Underhood Lamp Inoperative

Underhood Lamp Inoperative

Vanity Mirror Lamp(s) Inoperative

Vanity Mirror Lamp(s) Inoperative

Removal Procedure

1. Disconnect the battery negative cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure»(/chevrolet/cutaway-g3500/1997-2012/remont/charging-system/#battery-charging-system-and-starting-system) .
2. Disconnect the electrical connector from the stop lamp switch.
3. Remove the retainer from the brake pedal pin.
4. Remove the stop lamp switch and the pushrod to the power brake booster from the brake pedal pin.
5. Unsnap the stop lamp switch from the power brake booster pushrod.

Installation Procedure

1. Snap the stop lamp switch onto the pushrod to the power brake booster.
2. Install the stop lamp switch with the pushrod on the brake pedal pin.
3. Install brake switch retainer.
4. Connect the electrical connector to the stop lamp switch.
5. Connect the battery negative cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure»(/chevrolet/cutaway-g3500/1997-2012/remont/charging-system/#battery-charging-system-and-starting-system) .

1. Remove the instrument panel cluster trim plate. Refer to «Trim Plate Bezel Replacement - Instrument Panel (I/P) Cluster»(/chevrolet/cutaway-g3500/1997-2012/remont/gauges-instrument-panels/#instrument-panel-system-displays-gauges-and-console) in Instrument Panel, Gages and Console.
2. Disconnect the electrical connector from the headlamp switch.
3. Remove the headlamp switch from the instrument panel cluster trim plate by releasing the retainers on the instrument panel cluster trim plate from the headlamp switch.
4. Remove the headlamp switch from the vehicle.

1. Install the headlamp switch to the vehicle.
2. Connect the headlamp switch to the instrument panel cluster trim plate by pushing on the switch in order to engage the retainers on the instrument panel cluster trim plate.
3. Connect the electrical connector to the headlamp switch.
4. Install the instrument panel cluster trim plate. Refer to «Trim Plate Bezel Replacement - Instrument Panel (I/P) Cluster»(/chevrolet/cutaway-g3500/1997-2012/remont/gauges-instrument-panels/#instrument-panel-system-displays-gauges-and-console) in Instrument Panel, Gages and Console.

1. Pry the bezel from the instrument panel extension using a flat-bladed tool.
2. Remove the electrical connector from the rear fog lamp switch.
3. Press the tabs on the rear fog lamp switch in order to disengage the tabs from the bezel.
4. Remove the rear fog lamp switch from the vehicle.

1. Install the following components to the instrument panel extension: The rear fog lamp switch The bezel
2. Apply pressure to the rear fog lamp switch in order to engage the tabs on the switch to the bezel.
3. Install the rear fog lamp switch.
4. Install the electrical connector to the rear fog lamp switch.
5. Install the bezel to the lower panel extension.

1. Remove the left knee bolster bracket. Refer to «Knee Bolster Bracket Replacement - Left»(/chevrolet/cutaway-g3500/1997-2012/remont/gauges-instrument-panels/#instrument-panel-system-displays-gauges-and-console) in Instrument Panel, Gages, and Console.
2. Remove the turn/hazard flasher (2) from the Instrument Panel (I/P) Support.
3. Disconnect the electrical connector (1).
4. Remove the turn/hazard flasher (2).

1. Connect the electrical connector (1) to the turn / hazard Flasher (2).
2. Install the turn / hazard flasher (2) to the Instrument Panel (I/P) Support.
3. Install the left knee bolster bracket. Refer to «Knee Bolster Bracket Replacement - Left»(/chevrolet/cutaway-g3500/1997-2012/remont/gauges-instrument-panels/#instrument-panel-system-displays-gauges-and-console) in Instrument Panel, Gages, and Console.

1. Gently pry out the lens (2) of the vanity mirror assembly (4) with a suitable flat-bladed tool.
2. Remove the bulb (3) from the socket.

1. Install the bulb (3) into the bulb socket.
2. Install the lens (2) to the vanity mirror assembly (4) by pressing it into place.

1. Using a flat bladed tool, pry the dome lamp lens open.
2. Remove the dome lamp lens (2) completely from the dome lamp housing.
3. Partially remove the dome lamp housing (1) from the headliner.
4. Disconnect the electrical connector (2) from the dome lamp housing.

1. Partially install the dome lamp housing (1) to the headliner.
2. Connect the dome lamp electrical connector (2).
3. Install the dome lamp lens (2) to the dome lamp housing.
4. Snap the dome lamp lens (2) into the dome lamp housing.

1. Using a flat bladed tool, pry the dome lamp lens open.
2. Remove the dome lamp bulbs (1) from the dome lamp housing.

1. Install the dome lamp bulbs (1).
2. Snap the dome lamp lens (2) into the housing.

1. Disconnect the electrical connector from the underhood lamp.
2. Drill out the rivets (2) that retain the underhood lamp (1) to the hood.

1. Install the underhood lamp with the retaining rivets (2) to the hood.
2. Connect the electrical connector to the underhood lamp.

1. Turn OFF the headlamp switch.
2. Remove the retaining ring screws from the headlamp. Do not move the adjustment screws.
3. Remove the retaining ring from the headlamp.
4. Remove the headlamp from the housing.
5. Disconnect the electrical connector from the headlamp.

1. Connect the electrical connector to the headlamp.
2. Install the headlamp to the housing.
3. Install the retaining ring to the headlamp.
4. Install the screws to the retaining ring.

1. Turn OFF the headlamp switch.
2. Disconnect the electrical connector from the headlamp bulb.
3. Rotate the bulb counterclockwise in order to disengage the bulb from the headlamp.
4. Remove the bulb from the headlamp.

1. Install the bulb to the headlamp.
2. Rotate the bulb clockwise in order to engage the bulb in the headlamp.
3. Connect the electrical connector to the headlamp bulb.

1. Turn OFF the headlamp switch.
2. Remove the bolts (5) that retain the composite headlamp to the radiator support. Do not move the adjustment screws.
3. Disconnect the electrical connector (1) from the headlamp assembly.
4. Remove the composite headlamp (4) from the vehicle.

1. Connect the electrical connector (1) to the headlamp assembly.
2. Install the composite headlamp (4) to the vehicle.
3. Install the composite headlamp retaining bolts (5) to the radiator support. Tighten: Tighten the bolts to 11 N.m (97 lb in).

Headlamp Aiming

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 vehicle's low beam lamps. The high beam lamps will be correctly aimed if the low beam lamps are aimed properly. If the high beam needs adjustment, follow the screen method using the high beam bulb as the reference for measurements.

Screen Method for Headlamp Aiming (Visual Aim)

Headlamp aim should be checked

1. When a new headlamp capsule is installed
2. If service or repairs to the front end area have (or may have) disturbed the headlamps or their mounting

Scheme 22

1. The area will consist of a level surface large enough to allow for a vehicle and an additional 7.62 m (25 feet) measured from face of lamps to the front of the aiming screen.
2. The screen will be 1.52 m (5 ft) high x 3.66 m (12 ft) wide with a matte white surface well shaded from extraneous light, and properly adjusted to the floor on which the vehicle stands. Provisions may be made for moving the screen so it can be aligned parallel with the vehicle.
3. The screen shall be provided with a fixed vertical centerline, two laterally adjustable vertical tapes, and one vertically adjustable horizontal tape.
4. If a regular commercial aiming screen is not available, the screen may consist of a vertical wall having a clear uninterrupted area approximately 1.83 m (6 ft) high and 3.66 m (12 ft) wide. The surface should be finished with a washable non-gloss white paint.
5. After the aiming screen has been set up in its permanent location, it is necessary to paint a reference line on the floor directly under the lens of the lamps to indicate the proper location of the headlamps when they are being aimed: Distance between headlamps (1) Center line of screen (2) Adjustable vertical pointer (3) Adjustable horizontal tape (4) Diagram of light screen (5) Vertical center line ahead of right headlamp pointer position (6) 7.62 m (25 ft) (7) Car axis (8) Adjustable vertical pointer Horizontal center line of lamps Vertical center line ahead of left headlamp

Prior to aiming the headlamps, the following steps must be taken

1. Remove any snow, ice or mud from the vehicle.
2. The vehicle must have a full tank of gas.
3. Stop all other work on the vehicle.
4. If any service has been performed on the vehicle, make sure that all of the components are back in their original place.
5. The vehicle must be on a level surface.
6. The vehicle left tires must be aligned with the reference line extending from the screen with the headlamps aligned with the reference line.
7. Do not load any cargo in the vehicle.
8. The vehicle must contain one person or 72.56 kg (160 lb) on the driver's seat.
9. Inflate the tires to the proper pressure.
10. Simulate the vehicle loads if the intended use of the vehicle is for hauling heavy loads or towing a trailer.
11. Rock the vehicle in order to stabilize the suspension.
12. Turn on the headlamps to low beam and observe the left and the top edges of the high intensity zone on the screen. The edges of the high intensity zone should fall within the specifications.

Headlamp Aiming Procedure

1. Open the hood.
2. Measure from the floor to the center of the headlamp bulb. (Some headlamps have an aim dot marked on the headlamp lens).
3. At the screen, measure from the floor and place the horizontal tape at the measured distance.
4. Measure from the reference line on the floor to the left headlamp bulb centerline.
5. At the screen, measure from the reference line and place the vertical tape at the measured distance.
6. Measure from the reference line on the floor to the right headlamp bulb centerline.
7. At the screen, measure from the reference line and place the vertical tape at the measured distance.
8. Turn on the low beam headlamps and block the light from projecting onto the screen from the passenger side headlamp.
9. Adjust the vertical aim of the headlamps to the specifications required by the state and the local authorities, or as shown in step number 8.
10. Rotate the headlamp adjuster (1) to change the vertical aim of the headlamp.
11. Repeat the aiming procedure for the passenger side headlamp while blocking the light from projecting onto the screen from the driver side headlamp.
12. Close the hood.
13. This illustration represents the visual optics left (VOL) pattern.
14. This illustration represents the visual optics right (VOR) pattern.
15. This illustration represents all headlamps, except the VOL and VOR.
16. This illustration represents the high beam pattern for all headlamps, including VOL and VOR.

Tool Required

Composite Headlight Aimer Adapter

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, adjust the headlamps to the specifications required by state and local authorities.

1. Disconnect the electrical connector from the lamp assembly.
2. Remove the nut retaining the lamp assembly to the bracket.
3. Remove the lamp assembly from the bumper.

1. Install the lamp assembly to the bumper.
2. Install the nut to retain the lamp assembly to the bracket. Tighten: Tighten the nut to 2 N.m (18 in lb).
3. Install the electrical connector to the lamp assembly.

1. Remove the screws retaining the lens to the lamp.
2. Remove the lens from the lamp.
3. Gently push in on the bulb and turn the bulb 1/4 turn counterclockwise.
4. Remove the bulb from the socket.

1. Install the bulb to the socket.
2. Gently push in on the bulb and turn the bulb 1/4 turn clockwise.
3. Install the lens to the lamp assembly.
4. Install the screws to retain the lens to the lamp assembly. Tighten: Tighten the screws to 1.5 N.m (13 lb in).

1. Remove the screws holding the retaining ring to the headlamp housing assembly.
2. Remove the retaining ring from the position lamp.
3. Remove the headlamp capsule (1) from the position lamp.
4. Remove the bulb (4) and socket from the rubber grommet in the lamp capsule.
5. Push in on the side of the bulb (4) and turn the bulb 1/4 turn counterclockwise.
6. Remove the bulb (4) from the socket.

1. Install the bulb (4) to the socket.
2. Push in on the bulb (4) and turn 1/4 turn clockwise.
3. Install the bulb (4) and socket into the rubber grommet in the headlamp capsule (1).
4. Install the headlamp capsule (1) to the headlamp housing.
5. Install the retaining ring to the headlamp housing assembly.
6. Install the screws to the retaining ring to the headlamp housing assembly. Tighten: Tighten the screws to 1.5 N.m (13 lb in).

1. Push the light assembly (2) towards the front of the vehicle while gently prying the rear edge of the light assembly away from the fender with a small flat-bladed tool in order to remove the light assembly.
2. Remove the bulb and socket from the light assembly (3) by turning the socket 1/4 turn counterclockwise.
3. Remove the bulb (1) from the socket.

1. Install the bulb (1) into the socket.
2. Turn the socket (3) 1/4 turn clockwise in order to install the socket into the light assembly.
3. Hook the front tab on the lens into the fender and press the light assembly (2) retaining clip into the fender until fully seated.

1. Remove the screw (4) that retains the front side marker lamp to the radiator grille.
2. Lift the side marker lamp (3) up and out in order to disengage the tab.
3. Disconnect the bulb socket (1) from the side marker lamp.
4. Remove the bulb (1) from the socket.

1. Connect the bulb (1) into the socket.
2. Connect the bulb socket (1) into the side marker lamp.
3. Install the side marker lamp (3) to the radiator grille (5).
4. Install the side marker lamp retaining screw (4). Tighten: Tighten the screws to 1.5 N.m (13 lb in).

1. Remove the screw (4) that retains the side marker or the reflector to the grille.
2. Remove the side marker lamp (3) or the reflector (5) from the grille.
3. Disconnect the bulb socket (2) from the side marker lamp.
4. Remove the bulb (2) from the socket by turning the bulb in a counter clockwise direction.

1. Install the bulb (2) into the socket by turning the bulb in a clockwise direction.
2. Connect the bulb socket (2) into the side marker lamp.
3. Install the side marker lamp (3) or the reflector (5) to the radiator grille (1).
4. Install the side marker lamp or reflector retaining screw (4) to the grille. Tighten: Tighten the screws to 1.5 N.m (13 lb in).

1. Remove the park/turn signal lamp (3) from the grille.
2. Disconnect the bulb socket(s) (1) from the park/turn signal lamp by turning the bulb sockets in a counterclockwise direction.
3. Remove the bulb(s) (1) from the socket.

1. Install the bulb(s) (1) into the socket by turning the bulb sockets in a clockwise direction.
2. Connect the bulb socket(s) (1) into the park/turn signal lamp.
3. Install the park/turn signal lamp (3) to the grille (5).

1. Remove the screws (3) from the park/turn signal lamp to the grille.
2. Remove the park/turn signal lamp (2) from the grille.
3. Disconnect the bulb socket (1) from the park/turn signal lamp by turning the bulb sockets in a counterclockwise direction.
4. Remove the bulb (1) from the socket.

1. Install the bulb (1) into the socket by turning the bulb sockets in a clockwise direction.
2. Connect the bulb socket (1) into the park/turn signal lamp.
3. Install the park/turn signal lamp (2) to the grille (5).
4. Install the park/turn signal lamp retaining screws (3) to the grille. Tighten: Tighten the screws to 1.5 N.m (13 lb in).

1. Remove the screws (3) that retain the center high mounted stop lamp lens.
2. Remove the center high mounted stop lamp lens (2).
3. Disconnect the bulb socket (1) from the center high mounted stop lamp.
4. Remove the bulb (1) from the socket.

1. Install the bulb (1) into the socket.
2. Connect the bulb socket (1) into the center high mounted stop lamp lens.
3. Install the center high mounted stop lamp lens (2).
4. Install the center high mounted stop lamp lens retaining screws (3). Tighten: Tighten the center high mounted stop lamp lens screws to 1.5 N.m (13 lb in).

1. Disconnect the electrical connector.
2. Using a plastic flat bladed tool, release the double sided tape that retains the light assembly to the vehicle.

1. Install the light assembly into the vehicle with double sided tape.
2. Connect the electrical connector.

1. Disconnect the electrical connector from the lamp assembly.
2. Remove the nut retaining the lamp assembly to the bracket.
3. Remove the lamp assembly from the bumper.

1. Install the lamp assembly to the bumper.
2. Install the nut to the lamp. Tighten: Tighten the nut to 2 N.m (18 in lb).
3. Connect the electrical connector to the lamp assembly.

1. Remove the screws the lens to the lamp assembly.
2. Remove the lens from the lamp assembly.
3. Gently push in on the bulb and turn the bulb 1/4 turn counterclockwise.
4. Remove the bulb from the socket.

1. Install the bulb to the socket.
2. Gently push in on the bulb and turn the bulb 1/4 turn clockwise.
3. Install the lens to the lamp assembly.
4. Install the screws in order to retain the lens to the lamp assembly. Tighten: Tighten the screws to 1.5 N.m (13 lb in).

1. Remove the upper quarter panel applique. Refer to «Tail Lamp, Back Body Opening Applique Replacement - Side»(/chevrolet/cutaway-g3500/1997-2012/remont/exterior-body-panels/#body-rear-end) in Body Rear End.
2. Remove the nuts (2) that retain the tail lamp to the upper quarter panel.
3. Remove the center high mounted stop lamp lens (2) from the center high mounted stop lamp applique (1).
4. Disconnect the bulb sockets from the tail lamp (3).
5. Remove the bulbs from the sockets by turning the bulbs in a counterclockwise direction.

1. Install the bulbs into the sockets by turning the bulbs in a clockwise direction.
2. Connect the bulb sockets into the tail lamp (3).
3. Install the tail lamp retaining nuts (2) to the upper quarter panel. Tighten: Tighten the nuts to 5 N.m (44 lb in).
4. Install the upper quarter panel applique. Refer to «Tail Lamp, Back Body Opening Applique Replacement - Side»(/chevrolet/cutaway-g3500/1997-2012/remont/exterior-body-panels/#body-rear-end) in Body Rear End.

Exterior Lamps

The exterior lighting system consist of the following lamps

1. The headlamps
2. The daytime running lamps (DRL)
3. The park, tail and marker lamps
4. The turn signal/hazard lamps
5. The stop lamps
6. The backup lamps

Headlamps

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.

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 HDLP-HIBM 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 G101.

Low Beams

The low beam headlamps receive voltage from the HDLP-LOBM 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 G101.

Daytime Running Lamps (DRL)

The DRL are a function of the front turn signal lamps. 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 OFF position. When the BCM receives these signals it will signal the turn/hazard flasher module to turn on the DRL by grounding the DRL low control signal. The turn/hazard flasher module supplies voltage to the DRL on the right and left DRL/turn supply voltage circuits. If a front turn signal lamp is inoperative the DRL will not operate.

The DRL can be deactivated by turning the headlamp switch to the DRL OFF position while the DRL are operating. The DRL defeat position of the headlamp switch is a momentary ground signal to the BCM to command the DRL function ON or OFF. After each key cycle the BCM will default to the DRL ON function.

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. The headlamp and panel dimmer switch supplies a ground signal to the BCM on the park lamps switch on signal circuit. 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 these fuses in the body fuse block

1. FR PARK
2. LR PARK
3. RR PARK
4. TRLR PARK
5. UPFTR PRK

The front park and marker lamps are grounded at G100 and G101. The rear park and license lamps are grounded at G401 and 402.

Turn Signal/Hazard Lamps

The IGN E 10 A fuse in the underhood fuse block supplies battery positive voltage to the turn signal switch assembly. Ground for the hazard switch is from G302. The FLASHER 15 A fuse in the underhood fuse block supplies battery positive voltage to the turn/hazard flasher module. 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/hazard flasher module. When the hazard flasher switch is activated, a ground signal is completed from the hazard switch to the turn/hazard flasher module. The turn/hazard flasher module then sends an on-off voltage signal to the appropriate turn signal lamps, or to all turn signal lamps for hazard operation through these fuses

1. DR TRN MIR, in the body fuse block
2. PASS TRN MIR, in the body fuse block
3. LR STOP/TRN, in the body fuse block, and in the underhood fuse block for RPO UY7
4. RR STOP/TRN, in the body fuse block, and in the underhood fuse block for RPO UY7
5. LR TURN in the underhood fuse block
6. RR TURN in the underhood fuse block
7. LT DRL/TRN in the underhood fuse block
8. RT DRL/TRN in the underhood fuse block

The audio chime is also activated when the turn signals are on. When the hazard switch is pressed, all turn signal lamps will flash including both IPC turn indicators. The front turn signals are grounded at G100 and G101. The rear turn signals are grounded at G401 and 402. The mirror turn signals are grounded through a splice pack at G347.

Stop Lamps

The STOP LP 15 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 the STOP/CHMSL fuse and through the turn/hazard flasher module to the LR STOP/TRN and RR STOP/TRN fuses in the body fuse block or the LR TURN and RR TURN fuses in the underhood fuse block. The voltage from the STOP/CHMSL fuse is to the CHMSL and cruise control. The voltage from the LR STOP/TRN and RR STOP/TRN fuses is to the rear stop lamps. The voltage from the LR TURN and RR TURN fuses is to the trailer stop/turn relays. The rear stop lamps are grounded at G401 and 402. The CHMSL is grounded at G401

Backup Lamps

The B/U LP 20 A fuse in the underhood fuse block supplies battery positive voltage to the normally open park neutral position (PNP) switch. When driver places the gear selector lever is in the REVERSE position, the switch closes and the voltage is from the switch to the powertrain control module (PCM). The PCM signals the BCM on the class II serial data circuits that the backup lamps are requested. The BCM supplies voltage on the backup lamp supply voltage circuit to the backup lamps and to the automatic day/night mirror. The backup lamps are grounded at G401. Voltage for the backup lamp supply voltage, without RPO YF7 the courtesy lamp supply voltage, and with RPO YF7 the courtesy lamp high control circuits is from the TBC 2 fuse 18 in the underhood fuse block directly through the BCM to these circuits.

Interior Lamps

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

1. Courtesy/illuminated entry lamps
2. Dome lamps
3. Reading lamps
4. Vanity mirror lamps

Courtesy/Illuminated Entry Lamps (Without YF7)

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

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

The courtesy lamps are controlled and receive voltage from the BCM. The BCM receives signals from the mini wedges and door jamb switches when a door is opened or anytime the courtesy lamp on switch is placed in the ON position. Ground is provided to the cargo mini wedge at G402. Ground is provided to the remaining switches as well as all courtesy, reading and vanity lamps at G347.

Voltage for the courtesy lamp supply voltage and the backup lamp supply voltage circuits is from the TBC 2 fuse 18 in the underhood fuse block directly through the BCM to these circuits.

Courtesy/Illuminated Entry Lamps (With YF7)

The courtesy/illuminated entry lamps operate the same as above, however, the circuit functionality is different as follows

The CTSY LP/SEO 15A fuse in the body fuse block supplies battery positive voltage to the courtesy lamp relay switch input contacts. Ground is supplied to the courtesy lamp relay coil contact. The BCM supplies voltage on the courtesy lamp high control circuit to energize the courtesy lamp relay and supply voltage to the courtesy lamps. The BCM receives signals from the mini wedges and door jamb switches any time a door is opened, and anytime the courtesy lamp on switch is placed in the ON position. Ground is provided to the cargo mini wedge at G402. Ground is provided to the remaining switches as well as the stepwell lamps at G347.

Voltage for the courtesy lamp high control and the backup lamp supply voltage circuits is from the TBC 2 fuse 18 in the underhood fuse block directly through the BCM to these circuits.

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. 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 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. In the event that any of these lamps were to remain illuminated for a period of more than 10 minutes with the ignition switch in the OFF position, the BCM will deactivate the inadvertent power supply voltage circuit to prevent a total battery discharge condition. Ground is provided to the vanity lamps at G347.

Voltage for the inadvertent supply voltage circuit is from the TBC 4 fuse 11 in the underhood fuse block directly through the BCM to this circuit.

Reading Lamps

The inadvertent power 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. In the event that any of these lamps were to remain illuminated for a period of more than 10 minutes with the ignition switch in the OFF position, the BCM will deactivate the inadvertent power supply voltage circuit to prevent a total battery discharge condition. Ground is provided to the reading lamps at G347.

Voltage for the inadvertent supply voltage circuit is from the TBC 4 fuse 11 in the underhood fuse block directly through the BCM to this circuit.

Underhood Lamp

The inadvertent supply voltage circuit of the BCM provides battery positive voltage to the underhood lamp. When the hood is opened, a switch integral to the lamp closes to provide a ground circuit and the lamp illuminates. Ground is provided to the lamp at G347.

Voltage for the inadvertent supply voltage circuit is from the TBC 4 fuse 11 in the underhood fuse block directly through the BCM to this circuit.

Dome Fluorescent Work Lamps Components

The dome fluorescent work lamps system consists of the following components

1. The body control module (BCM) - Class 2 module that requires programming when replaced
2. The AUXILIARY 1 Fuse 32 50A - Located in the body fuse block and is hot at all times
3. The DOME FLUORESCENT WORK LAMPS fuse 2 10A fuse - Located in the rear fuse block and is hot at all times
4. The Dome Fluorescent Work Lamp Relay - Located below the rear fuse block
5. The dome fluorescent work lamps - With on/off switches integrated into each lamp assembly

Dome Fluorescent Work Lamps Controls

Each dome fluorescent work lamps is equipped with an integral ON/OFF switch. The work lamps will remain on until manually turned off as long as the key is in the RUN position. The work lamps will also remain on for approximately 10 minutes after the ignition key has been turned to the OFF or ACCY positions. If the work lamp is turned ON with the ignition switch either in the OFF or ACCY positions, within 2 minutes after a 10 minute time out, the work lamp will turn on and remain on until the battery fully discharges.

Dome Fluorescent Work Lamps Operation

Voltage is supplied to the relay switch and coil side from the dome fluorescent work lamp10 A fuse 2 in the rear fuse block. When the work lamp on switch is pressed the BCM senses this signal on the dome fluorescent work lamp signal circuit. The BCM responds to this signal by grounding the dome fluorescent work lamp relay control circuit, energizing the relay. The relay in turn supplies voltage to the work lamps. The BCM utilizes the dome fluorescent work lamps signal circuit as a request signal when the key is in the any position except START. The work lamps are grounded at G403.

Battery Rundown Protection/Inadvertent Power

The BCM inadvertent power supply voltage circuit provides battery positive voltage to all of the interior reading lamps, 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 10 minutes with the ignition switch in the OFF position, the BCM will deactivate the inadvertent power supply voltage circuit to prevent a total battery discharge condition.

The BCM also utilizes the inadvertent power supply voltage circuit as a lamp request signal circuit when the ignition key is in the OFF position. When a lamp switch is activated, the BCM receives the request for lamp illumination and switches to supplying voltage to the inadvertent power supply voltage circuit.

Interior Lamps Dimming

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

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

The following switches and components have dimmable back lighting

1. The traction control switch
2. The instrument panel cluster (IPC)
3. The radio controls
4. The headlamp and panel dimmer switch
5. The HVAC control assemblies
6. The inflatable restraint disable switch
7. The tow/haul switch
8. The window and door lock switches
9. The rear heater switch
10. The rear seat audio control

The I/P cluster illumination lamps, various switches and control assemblies receive voltage and are controlled by the BCM on the instrument panel lamps dimming control circuit and the backlight lamps control circuit.

Voltage for the LED dimming signal, instrument panel lamps dimming control, as well as the backlight lamps control circuits is from the TBC 3 fuse 16 in the underhood fuse block directly through the BCM to these circuits.

Special Tools

Special Tools Illustration Tool Number/ Description J 25300-E Headlamp Aimer

See also:
• Scan Tool Does Not Power Up
• Body Control System Description and Operation
• Diagnostic Trouble Code (DTC) List
• Testing for Intermittent Conditions and Poor Connections
• Connector Repairs
• Circuit Testing
• Wiring Repairs
• Relay Replacement (Within an Electrical Center)
• Testing for Continuity
• Checking Aftermarket Accessories
• Lock Replacement - Front Door
• Testing for Electrical Intermittents
• Park Brake Warning Lamp Switch Replacement
• Multifunction, Turn Signal Switch Replacement
• Instrument Panel Cluster (IPC) Replacement
• Testing for Short to Ground
• Instrument Panel, Gages, and Console Connector End Views
• Sunshade Replacement
• Battery Negative Cable Disconnect/Connect Procedure
• Halogen Bulb Caution
• Fastener Notice
• Tail Lamp, Back Body Opening Applique Replacement - Side
• Diagnostic System Check - Lighting Systems
• Diagnostic Trouble Code (DTC) List
• Interior Lights Dimming Schematics
• Interior Lights Schematics
• Headlights Schematics
• Exterior Lights Schematics
• Backup Lamps Always On
• Backup Lamps Inoperative
• Courtesy Lamps Always On
• Courtesy Lamps Inoperative (Lamps)
• Courtesy Lamps Inoperative (Defeat Switch)
• Daytime Running Lamps (DRL) Inoperative (Lamps)
• Daytime Running Lamps (DRL) Inoperative (Defeat Switch)
• Dome Lamps Always On
• Dome Lamps Inoperative
• Hazard Lamps Always On
• Hazard Lamps Inoperative
• Headlamps Always On - Low or High Beam
• Headlamps Inoperative - High Beams
• Headlamps Inoperative - Low Beams
• Headlamps Inoperative - Low and High Beams
• Headlamps Inoperative - Flash to Pass
• High Beam Indicator Always On
• High Beam Indicator Inoperative
• Interior Backlighting Does Not Dim
• Interior Backlighting Inoperative
• Park, License, and Tail Lamps Always On
• Park, License, and Tail Lamps Inoperative
• Reading Lamp(s) Inoperative
• Stop Lamps Always On
• Stop Lamps Inoperative
• Turn Signal Lamps and/or Indicators Always On or Flashing
• Turn Signal Lamps and/or Indicators Inoperative
• Underhood Lamp Inoperative
• Vanity Mirror Lamp(s) Inoperative
• Scan Tool Data List