Lighting Systems Chevrolet Cobalt I

Fastener Tightening Specifications

Fastener Tightening Specifications

Lighting Systems Schematic Icons Icon Icon Definition CAUTION: When performing service on or near the SIR components or the SIR wiring, the SIR system must be disabled. Refer to SIR Disabling and Enabling Zones. Failure to observe the correct procedure could cause deployment of the SIR components, personal injury, or unnecessary SIR system repairs

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Ambient Light Sensor Connector Part Information OEM: 12059249 Service: See Catalog 2-Way F Metri-Pack 150 Series (NA) Pin Wire Color Circuit No. Function A L-GN/BK 1137 DRL Ambient Light Sensor Signal B YE/BK 1138 DRL Ambient Light Sensor Low Reference

Backup Lamp - Left (Coupe) Connector Part Information OEM: 12052641 Service: See Catalog 2-Way F Metri-Pack 150 Series Sealed (BK) Pin Wire Color Circuit No. Function A L-GN 24 Backup Lamp Supply Voltage B BK 750 Ground

Backup Lamp - Right (Coupe) Connector Part Information OEM: 12052641 Service: See Catalog 2-Way F Metri-Pack 150 Series Sealed (BK) Pin Wire Color Circuit No. Function A L-GN 24 Backup Lamp Supply Voltage B BK 850 Ground

Backup Lamp Switch (L61 w/M86) Connector Part Information OEM: 12052641 Service: See Catalog 2-Way F Metri-Pack 150 Series Sealed (BK) Pin Wire Color Circuit No. Function A PK 539 Ignition 1 Voltage B L-GN 24 Backup Lamp Supply Voltage

Brake Switch C1 Connector Part Information OEM: 12041433 Service: See Catalog 2-Way F Metri-Pack 280 Series Sealed (BK) Pin Wire Color Circuit No. Function A PK 439 Ignition 1 Voltage B L-GN 420 TCC Brake Switch/Cruise Control Release Switch Signal

Brake Switch C2 Connector Part Information OEM: 12033706 Service: See Catalog 4-Way F Metri-Pack 280 Series Sealed (BU) Pin Wire Color Circuit No. Function A PK 439 Ignition 1 Voltage B PU 420 TCC Brake Switch/Cruise Control Release Switch Signal C-D - - Not Used

Center High Mounted Stop Lamp (CHMSL) Connector Part Information OEM: 12059110 Service: See Catalog 2-Way F Metri-Pack 150 Series (BK) Pin Wire Color Circuit No. Function A L-BU 20 Stop Lamp Supply Voltage B BK 750 Ground

Dome Lamp Connector Part Information OEM: 12045813 Service: See Catalog 4-Way F Metri-Pack 150 Series (NA) Pin Wire Color Circuit No. Function A BK 750 Ground B GY 157 Interior Lamp Control C - - Not Used D D-BU/WH 149 Courtesy Lamp Supply Voltage

Door Jamb Switch - Driver Connector Part Information OEM: 15449028 Service: See Catalog 2-Way F GT 150 Series Sealed (BK) Pin Wire Color Circuit No. Function A GY/BK 745 Left Front Door Ajar Switch Signal B BK/WH 650 Ground

Door Jamb Switch - LR (Sedan) Connector Part Information OEM: 15449028 Service: See Catalog 2-Way F GT 150 Series Sealed (BK) Pin Wire Color Circuit No. Function A L-BU/BK 747 Left Rear Door Ajar Switch Signal B BK 650 Ground

Door Jamb Switch - Passenger Connector Part Information OEM: 15449028 Service: See Catalog 2-Way F GT 150 Series Sealed (BK) Pin Wire Color Circuit No. Function A TN/WH 746 Right Front Door Ajar Switch Signal B BK 650 Ground

Door Jamb Switch - RR (Sedan) Connector Part Information OEM: 15449028 Service: See Catalog 2-Way F GT 150 Series Sealed (BK) Pin Wire Color Circuit No. Function A L-GN/BK 748 Right Rear Door Ajar Switch Signal B GY/BK 1798 Low Reference

Fog Lamp - LF Connector Part Information OEM: 12124819 Service: See Catalog 2-Way F Metri-Pack 280 Series Sealed (BK) Pin Wire Color Circuit No. Function A PU 2234 Front Fog Lamp Supply Voltage B BK 150 Ground

Fog Lamp - RF Connector Part Information OEM: 12124819 Service: See Catalog 2-Way F Metri-Pack 280 Series Sealed (BK) Pin Wire Color Circuit No. Function A PU 2234 Front Fog Lamp Supply Voltage B BK 250 Ground

Fog Lamp Switch (T37) Connector Part Information OEM: 15419483 Service: See Catalog 4-Way F Metri-Pack 150 Series (BK) Pin Wire Color Circuit No. Function A BK/WH 1051 Signal Ground B - - Not Used C OG 192 Front Fog Lamp Switch Signal D GY 8 Instrument Panel Lamp Supply Voltage (1)

Hazard Switch Connector Part Information OEM: 12089248 Service: See Catalog 4-Way F Metri-Pack 150 Series (NA) Pin Wire Color Circuit No. Function A BK 550 Ground B GY 8 Instrument Panel Lamp Supply Voltage (1) C - - Not Used D WH 111 Hazard Switch Signal

Headlamp High/Low Beam - Right Connector Part Information OEM: 12048369 Service: See Catalog 3-Way F Metri-Pack 280 Series Sealed (BU) Pin Wire Color Circuit No. Function A OG - - B BK - - C PK

Headlamp High/Low Beam - Left Connector Part Information OEM: 12048369 Service: See Catalog 3-Way F Metri-Pack 280 Series Sealed (BU) Pin Wire Color Circuit No. Function A OG - - B BK - - C PK

I/P Dimmer Switch Connector Part Information OEM: 15332135 Service: See Catalog 4-Way F GT 150 Series (BK) Pin Wire Color Circuit No. Function A-B - - Not Used C PU 719 Sensor Low Reference D D-GN 44 Instrument Panel Lamp Dimmer Switch Signal

License Lamp Connector Part Information OEM: 12052641 Service: See Catalog 2-Way F Metri-Pack 150 Series Sealed (BK) Pin Wire Color Circuit No. Function A BN 9 Park Lamp Supply Voltage B BK 750 Ground

Marker Lamp - LR (Coupe) Connector Part Information OEM: 12052641 Service: See Catalog 2-Way F Metri-Pack 150 Series Sealed (BK) Pin Wire Color Circuit No. Function A BN 9 Park Lamp Supply Voltage B BK 750 Ground

Marker Lamp - RR (Coupe) Connector Part Information OEM: 12052641 Service: See Catalog 2-Way F Metri-Pack 150 Series Sealed (BK) Pin Wire Color Circuit No. Function A BN 9 Park Lamp Supply Voltage B BK 850 Ground

Marker Lamp - LR (Sedan) Connector Part Information OEM: 12052641 Service: See Catalog 2-Way F Metri-Pack 150 Series Sealed (BK) Pin Wire Color Circuit No. Function A BN 9 Park Lamp Supply Voltage B BK 750 Ground

Marker Lamp - LR (Sedan) Connector Part Information OEM: 12052641 Service: See Catalog 2-Way F Metri-Pack 150 Series Sealed (BK) Pin Wire Color Circuit No. Function A BN 9 Park Lamp Supply Voltage B BK 750 Ground

Marker Lamp - LF Connector Part Information OEM: 16530675 Service: See Catalog 2-Way F (GY) Pin Wire Color Circuit No. Function A BK - - BK - - B BN

Marker Lamp - RF Connector Part Information OEM: 16530675 Service: See Catalog 2-Way F (GY) Pin Wire Color Circuit No. Function A BK - - BK - - B BN

Park /Turn Signal DRL Lamp - LF Connector Part Information OEM: 0001340 Service: See Catalog 3-Way F CE-F22.2 Series Bulb socket (BG) Pin Wire Color Circuit No. Function A L-BU - - B BN - - BN - - C BK - - BK

Park/Turn Signal DRL Lamp - RF Connector Part Information OEM: 0001340 Service: See Catalog 3-Way F CE-F22.2 Series Bulb socket (BG) Pin Wire Color Circuit No. Function A YE 18 Left Rear Stop/Turn Lamp Supply Voltage B BN 9 Park Lamp Supply Voltage C BK 750 Ground

Stop Lamp Switch Connector Part Information OEM: 12033701 Service: See Catalog 2-Way F Metri-Pack 480 Series (GY) Pin Wire Color Circuit No. Function A RD/WH 140 Battery Positive Voltage B L-BU 20 Stop Lamp Supply Voltage

Tail/Stop and Turn Signal Lamp - Left (Coupe) Connector Part Information OEM: 12040977 Service: See Catalog 3-Way F Metri-Pack 280 Series Sealed (BK) Pin Wire Color Circuit No. Function A YE 18 Left Rear Stop/Turn Lamp Supply Voltage B BN 9 Park Lamp Supply Voltage C BK 750 Ground

Tail/Stop and Turn Signal Lamp - Right (Coupe) Connector Part Information OEM: 12040977 Service: See Catalog 3-Way F Metri-Pack 280 Series Sealed (BK) Pin Wire Color Circuit No. Function A D-GN 19 Right Rear Stop/Turn Lamp Supply Voltage B BN 9 Park Lamp Supply Voltage C BK 850 Ground

Tail/Stop and Turn Signal Lamp - Left (Sedan) Connector Part Information OEM: 16530671 Service: See Catalog 3-Way F (GY) Pin Wire Color Circuit No. Function A YE 18 Left Rear Stop/Turn Lamp Supply Voltage B BN 9 Park Lamp Supply Voltage C BK 750 Ground

Tail/Stop and Turn Signal Lamp - Right (Sedan) Connector Part Information OEM: 16530671 Service: See Catalog 3-Way F (GY) Pin Wire Color Circuit No. Function A YE 19 Left Rear Stop/Turn Lamp Supply Voltage B BN 9 Park Lamp Supply Voltage C BK 850 Ground

Turn Signal/Multifunction Switch C1 Connector Part Information OEM: 15450317 Service: See Catalog 8-Way F Misc (WH) Pin Wire Color Circuit No. Function 1 BK/WH 651 Signal Ground 2 WH 103 Headlamp Switch On Signal 3 BN/WH 301 Park Lamp Switch On Signal 4 PU/WH 549 Headlamp Switch Headlamps Off Signal 5-8 - - Not Used

Turn Signal/Multifunction Switch C2 Connector Part Information OEM: 15393435 Service: See Catalog 10-Way F Micro-Pack 064 Series (GY) Pin Wire Color Circuit No. Function A - - Not Used B BK/WH 651 Signal Ground C BN 1356 Flash To Pass Switch Signal D PU 524 Headlamp Dimmer Switch High Beam Signal E PK/WH 1970 Headlamp Low Beam Relay Control F YE 10 Headlamp Switch Signal G YE/BK 1418 Left Rear Turn Signal Switch Signal H D-GN/WH 1419 Right Rear Turn Signal Switch Signal J-K - - Not Used

Begin the system diagnosis with the Diagnostic System Check - Vehicle in Vehicle DTC Information. The Vehicle System Check will provide the following information

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

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

Scan Tool Output Controls

Body Control Module (BCM)

Scan Tool Data List

Body Control Module (BCM)

Circuit Description

The body control module (BCM) supplies battery positive voltage to the courtesy lamps, underhood lamp, instrument panel (I/P) compartment lamp, console 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 courtesy lamps supply voltage circuit to prevent a total battery discharge condition.

DTC Descriptor

This diagnostic procedure supports the following DTC

DTC B1480 Battery Rundown Protection Circuit

Conditions for Running the DTC

The battery voltage must be between 9-16 volts.

DTC B1480 00

The inadvertent power courtesy lamps supply voltage circuit to the courtesy lamps, underhood lamp, I/P compartment lamp, console lamp, and both visor vanity mirror lamps are shorted to ground for longer than 1 second.

Action Taken When the DTC Sets

The courtesy lamps, underhood lamp, I/P compartment lamp, console lamp, and both visor vanity mirror lamps will not operate.

Conditions for Clearing the 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.

Diagnostic Aids

Perform a visual inspection for loose or poor connections at all related components. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

DTC B1480

The front fog lamp switch signal circuit is grounded momentarily by pressing the front fog lamp switch. The body control module (BCM) energizes the front fog lamp relay by applying battery positive voltage to the front fog lamps relay control circuit when the front fog lamp relay is energized, battery positive voltage is applied to the front fog lamps supply voltage circuit which illuminates the front fog lamps.

This diagnostic procedure supports the following DTC

DTC B2530 Front Fog Lamps Control Circuit

The battery voltage must be between 9-16 volts.

DTC B2530 02

The front fog lamp relay control circuit is shorted to ground.

DTC B2530 05

The front fog lamp relay control circuit is shorted to battery positive voltage or open.

The front fog lamps will not operate.

The front fog lamps and the fog lamp indicator will be on at all times or will not operate.

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 DTCs can be cleared using a scan tool.

1. The fog lamps will only illuminate under the following conditions: The park lamps or low beam headlamps are ON. The high beam headlamps are OFF. The fog lamp switch is the ON position.
2. If the DTC is a history DTC, the problem may be intermittent. Refer to «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/cobalt/i-2004-2010/remont/electrical-component-locations/#wiring-systems-electrical-power-management__testing-for-intermittent-conditions-and-poor) in Wiring Systems.

DTC B2530

The body control module (BCM) controls the rear compartment courtesy lamp. The BCM supplies voltage to control the lighting functions. The BCM monitors the rear compartment lamp control circuit for proper operation.

This diagnostic procedure supports the following DTC

DTC B2570 Trunk Lamp Output

Conditions for Setting the DTC

1. B2570 02 will set if there is a short to ground in the rear compartment lamp control circuit.
2. B2570 05 will set if there is an open or short to voltage in the rear compartment lamp control circuit.

1. The rear compartment lamp control circuit output will be disabled.
2. Stores a DTC B2570 in the BCM memory

1. This DTC requires an ignition cycle in order to change from current to history.
2. The BCM no longer detects continuous battery voltage on the rear compartment lamp control circuit.
3. A history DTC will clear after 50 consecutive ignition cycles if the condition for the malfunction is no longer present.

DTC B2570

The high beam relay is controlled by the body control module (BCM). The BCM provides ground to the high beam relay control circuit in order to turn ON the high beam relay. When the high beam relay control circuit opens, becomes shorted to voltage, or becomes shorted to ground without being commanded ON by the BCM, DTC B2580 is set.

This diagnostic procedure supports the following DTC

DTC B2580 Headlamp High Beam Control Circuit

The ignition switch is in the ON position.

B2580 01

Will set if there is a short to voltage in the high beam relay control circuit

B2580 06

Will set if there is an open or short to ground in the high beam relay control circuit

1. DTC B2580 is stored in the BCM memory.
2. If the high beam relay control circuit is shorted to ground, the high beams are always ON.
3. If the high beam relay control circuit is open, the high beam lamps are inoperative.

1. The conditions for setting the DTC are no longer present.
2. A history DTC clears after 100 malfunction-free ignition cycles.
3. The BCM receives the clear code command from the scan tool.

1. The high beam lamps will only illuminate under the following conditions: The headlamps are ON. The headlamp dimmer switch is in the high position.
2. If the DTC is a history DTC, the problem may be intermittent. Refer to «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/cobalt/i-2004-2010/remont/electrical-component-locations/#wiring-systems-electrical-power-management__testing-for-intermittent-conditions-and-poor) in Wiring Systems.

DTC B2580

The body control module (BCM) monitors the instrument panel (I/P) lamps dimming control circuit to determine the lighting intensity of the I/P lamps. When the BCM receives a varied voltage signal on the I/P lamps dimming control circuit, it applies a corresponding pulse width modulated (PWM) voltage signal through the I/P lamps supply voltage circuit to all the I/P lamps.

This diagnostic procedure supports the following DTC

DTC B2625 Display Dimming Pulse Width Modulation (PWM) Output Circuit

1. Voltage supplied to the BCM is in the normal operating range, approximately 9-14 volts.
2. The ignition switch must be in the ACCESSORY or RUN position.
3. The park lamps must be ON.

1. The BCM detects a short to ground in the instrument panel lamp supply voltage circuit.
2. The above condition must be present for more than 1 second.

1. The I/P courtesy lamps are inoperative.
2. The BCM store DTC B2625 in memory.

Conditions for Clearing the MIL/DTC

1. A current DTC B2625 clears when the BCM no longer detects a short to ground in the I/P lamps supply voltage circuit.
2. A history DTC B2625 clears after 100 consecutive ignition cycles.

1. If the DTC B2627 is a history DTC, the fault may be intermittent. Refer to «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/cobalt/i-2004-2010/remont/electrical-component-locations/#wiring-systems-electrical-power-management__testing-for-intermittent-conditions-and-poor) in Wiring Systems.
2. The following conditions may cause an intermittent malfunction to occur: An intermittent short to ground in the instrument panel lamps supply voltage circuit. The BCM is intermittently shorted to ground.

DTC B2625

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.

This diagnostic procedure supports the following DTC

DTC B2645 Ambient Light Sensor Circuit

The system voltage must be between 9-16 volts.

B2645 01

Will set if there is a short to voltage in the ambient light sensor signal circuit

B2645 02

Will set if there is an open or short to ground in the ambient light sensor signal circuit

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.

1. The following may cause an intermittent: Bent terminal Backed out terminal Damaged terminal Poor terminal tension Chafed wire Broken wire inside the insulation
2. When diagnosing for an intermittent short or an open, manipulate the wire harness while watching the test equipment for changes.

DTC B2645

The body control module (BCM) supplies voltage to the center high mount stop lamp (CHMSL) and the powertrain control module (PCM) when the stop lamps are active.

This diagnostic procedure supports the following DTC

DTC B3903 Stop Lamp Relay Circuit

1. The BCM must be powered.
2. This test is run continuously.

B3903 02

Will set if the stop lamp switch signal circuit is shorted to ground for 125 ms

B3903 05

Will set if the stop lamp switch signal circuit is open or shorted to voltage for 125 ms

When DTC B3903 is set the service vehicle soon lamp will illuminate.

1. The current DTC will clear when the fault is no longer present.
2. The ignition key must be cycled OFF and ON.
3. A history DTC clears after 100 consecutive ignition cycles in which no faults have occurred.
4. Clear the DTC with a scan tool.

DTC B3903

The body control module (BCM) controls the left front turn signal, hazard lamp, and daytime running lamp (DRL). The BCM supplies voltage to control the lighting functions. The BCM monitors the left turn signal lamp supply voltage circuit for proper operation.

This diagnostic procedure supports the following DTC

DTC B3948 Left Front Turn Signal Circuit

B3948 02

Will set if there is a short to ground in the left front turn signal circuit

B3948 05

Will set if there is an open or short to voltage in the left front turn signal circuit

1. The Service Vehicle Soon message will be displayed.
2. Stores a DTC B3948 in the BCM memory
3. If the failure is an open, short to ground, or to power, the rear turn signal flashes at double rate.

1. This DTC requires an ignition cycle in order to change from current to history.
2. The BCM no longer detects continuous battery voltage on the LH turn signal monitor circuit for longer than 5 seconds.
3. A history DTC will clear after 50 consecutive ignition cycles if the condition for the malfunction is no longer present.

1. The following conditions may cause an intermittent malfunction: There is an intermittent short to voltage in the LH turn signal monitor circuit. The turn signal switch or the hazard switch is shorted internally or is sticking.
2. If the BCM detects continuous voltage on the LH turn signal monitor circuit, the BCM interprets this as a short to voltage. The BCM will continue with normal DRL operation, and the LF turn signal will remain inoperative.
3. If the DTC is a history DTC, the problem may be intermittent. Perform the tests shown while moving related wiring and connectors. This can often cause the malfunction to occur. Refer to «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/cobalt/i-2004-2010/remont/electrical-component-locations/#wiring-systems-electrical-power-management__testing-for-intermittent-conditions-and-poor) in Wiring Systems.

DTC B3948

The body control module (BCM) controls the right front turn signal, hazard lamp, and daytime running lamp (DRL). The BCM supplies voltage to control the lighting functions. The BCM monitors the right turn signal lamp supply voltage circuit for proper operation.

This diagnostic procedure supports the following DTC

DTC B3949 Right Front Turn Signal Circuit

B3949 02

Will set if there is a short to ground in the right front turn signal circuit

B3949 05

Will set if there is an open or short to voltage in the right front turn signal circuit

1. The service vehicle soon message will be displayed.
2. Stores a DTC B3949 in the BCM memory
3. If the failure is an open, short to ground, or to power, the rear turn signal flashes at double rate.

1. This DTC requires an ignition cycle in order to change from current to history.
2. The BCM no longer detects continuous battery voltage on the RH turn signal monitor circuit for longer than 5 seconds.
3. A history DTC will clear after 50 consecutive ignition cycles if the condition for the malfunction is no longer present.

1. The following conditions may cause an intermittent malfunction: There is an intermittent short to voltage in the RH turn signal monitor circuit. The turn signal switch or the hazard switch is internally shorted or is sticking.
2. The BCM needs to detect voltage oscillations on the RH turn signal monitor circuit in order to de-energize the RH DRL relay. If the BCM detects continuous voltage on the RH turn signal monitor circuit, the BCM interprets this as a short to voltage. The BCM will continue with normal DRL operation, and the RF turn signal will remain inoperative.
3. If the DTC is a history DTC, the problem may be intermittent. Perform the tests shown while moving related wiring and connectors. This can often cause the malfunction to occur. Refer to «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/cobalt/i-2004-2010/remont/electrical-component-locations/#wiring-systems-electrical-power-management__testing-for-intermittent-conditions-and-poor) in Wiring Systems.

DTC B3949

The body control module (BCM) controls the left rear turn signal and hazard lamp. The BCM supplies voltage to control the lighting functions. The BCM monitors the left rear stop/turn lamp supply voltage circuit for proper operation.

This diagnostic procedure supports the following DTC

DTC B3950 Left Rear Turn Signal Circuit

B3950 02

Will set if there is a short to ground in the left rear turn signal circuit

B3950 05

Will set if there is an open or short to voltage in the left rear turn signal circuit

1. The Service Vehicle Soon message will be displayed.
2. Stores a DTC B3950 in the BCM memory
3. If the failure is an open, short to ground, or to power, the rear turn signal flashes at double rate.

1. This DTC requires an ignition cycle in order to change from current to history.
2. The BCM no longer detects continuous battery voltage on the LH turn signal monitor circuit for longer than 5 seconds.
3. A history DTC will clear after 50 consecutive ignition cycles if the condition for the malfunction is no longer present.

1. The following conditions may cause an intermittent malfunction: There is an intermittent short to voltage in the LH turn signal monitor circuit. The turn signal switch or the hazard switch is shorted internally or is sticking.
2. If the BCM detects continuous voltage on the LH turn signal monitor circuit, the BCM interprets this as a short to voltage. The BCM will continue with normal daytime running lights (DRL) operation, and the LR turn signal will remain inoperative.
3. If the DTC is a history DTC, the problem may be intermittent. Perform the tests shown while moving related wiring and connectors. This can often cause the malfunction to occur. Refer to «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/cobalt/i-2004-2010/remont/electrical-component-locations/#wiring-systems-electrical-power-management__testing-for-intermittent-conditions-and-poor) in Wiring Systems.

DTC B3950

The body control module (BCM) controls the right rear turn signal and hazard lamp. The BCM supplies voltage to control the lighting functions. The BCM monitors the right rear stop/turn lamp supply voltage circuit for proper operation.

This diagnostic procedure supports the following DTC

DTC B3951 Right Rear Turn Signal Circuit

B3951 02

Will set if there is a short to ground in the right rear turn signal circuit

B3951 05

Will set if there is an open or short to voltage in the right rear turn signal circuit

1. The Service Vehicle Soon message will be displayed.
2. Stores a DTC B3951 in the BCM memory
3. If the failure is an open, a short to ground, or to power, the rear turn signal flashes at double rate.

1. This DTC requires an ignition cycle in order to change from current to history.
2. The BCM no longer detects continuous battery voltage on the RH turn signal monitor circuit for longer than 5 seconds.
3. A history DTC will clear after 50 consecutive ignition cycles if the condition for the malfunction is no longer present.

1. The following conditions may cause an intermittent malfunction: There is an intermittent short to voltage in the RH turn signal monitor circuit. The turn signal switch or the hazard switch is internally shorted or is sticking.
2. If the BCM detects continuous voltage on the RR turn signal monitor circuit, the BCM interprets this as a short to voltage. The BCM will continue with normal daytime running lights (DRL) operation, and the RF turn signal will remain inoperative.
3. If the DTC is a history DTC, the problem may be intermittent. Perform the tests shown while moving related wiring and connectors. This can often cause the malfunction to occur. Refer to «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/cobalt/i-2004-2010/remont/electrical-component-locations/#wiring-systems-electrical-power-management__testing-for-intermittent-conditions-and-poor) in Wiring Systems.

DTC B3951

1. Perform the Vehicle System Check before using the symptom tables in order to verify that all of the following are true: There are no DTCs set. The body control module (BCM) 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/cobalt/i-2004-2010/remont/exterior-lights/#lighting-systems) «Interior Lighting Systems Description and Operation»(/chevrolet/cobalt/i-2004-2010/remont/exterior-lights/#lighting-systems)

Visual/Physical Inspection

Several of the symptom procedures ask for a careful visual/physical check. This step is extremely important; it could lead to correcting a problem without further checks and can save valuable time. These checks include the following

1. Inspect for aftermarket devices which could affect the operation of the Lighting System. Refer to «Checking Aftermarket Accessories»(/chevrolet/cobalt/i-2004-2010/remont/electrical-component-locations/#wiring-systems-electrical-power-management__checking-aftermarket-accessories) in Wiring Systems.
2. Inspect the easily accessible or visible system components and harness connectors for obvious damage or conditions which could cause the symptom.
3. If only one lamp is inoperative, inspect and repair a poor connection or an open in the power feed or ground circuit before replacing the light bulb. Refer to «Circuit Testing»(/chevrolet/cobalt/i-2004-2010/remont/electrical-component-locations/#wiring-systems-electrical-power-management__circuit-testing) and «Wiring Repairs»(/chevrolet/cobalt/i-2004-2010/remont/electrical-component-locations/#wiring-systems-electrical-power-management__wiring-repairs) in Wiring Systems.

Symptom List

Refer to a symptom diagnostic procedure from the following list in order to diagnose a symptom that does not set a DTC

1. «Backup Lamps Always On»(/chevrolet/cobalt/i-2004-2010/remont/exterior-lights/#lighting-systems__backup-lamps-always-on)
2. «Backup Lamps Inoperative»(/chevrolet/cobalt/i-2004-2010/remont/exterior-lights/#lighting-systems__backup-lamps-inoperative)
3. «Courtesy Lamps Always On»(/chevrolet/cobalt/i-2004-2010/remont/exterior-lights/#lighting-systems__courtesy-lamps-always-on)
4. «Courtesy Lamps Inoperative»(/chevrolet/cobalt/i-2004-2010/remont/exterior-lights/#lighting-systems__courtesy-lamps-inoperative)
5. «Fog Lamps Always On»(/chevrolet/cobalt/i-2004-2010/remont/exterior-lights/#lighting-systems__fog-lamps-always-on)
6. «Fog Lamps Inoperative»(/chevrolet/cobalt/i-2004-2010/remont/exterior-lights/#lighting-systems__fog-lamps-inoperative)
7. «Hazard Lamps Inoperative»(/chevrolet/cobalt/i-2004-2010/remont/exterior-lights/#lighting-systems__hazard-lamps-inoperative)
8. «Headlamps Always On - Low or High Beam»(/chevrolet/cobalt/i-2004-2010/remont/exterior-lights/#lighting-systems__headlamps-always-on-low-or)
9. «Headlamps Inoperative - High Beams»(/chevrolet/cobalt/i-2004-2010/remont/exterior-lights/#lighting-systems__headlamps-inoperative-high-beams)
10. «Headlamps Inoperative - Low Beams»(/chevrolet/cobalt/i-2004-2010/remont/exterior-lights/#lighting-systems__headlamps-inoperative-low-beams)
11. «Headlamps Inoperative - Low and High Beams»(/chevrolet/cobalt/i-2004-2010/remont/exterior-lights/#lighting-systems__headlamps-inoperative-low-and-high)
12. «Headlamps Inoperative - Flash to Pass»(/chevrolet/cobalt/i-2004-2010/remont/exterior-lights/#lighting-systems__headlamps-inoperative-flash-to-pass)
13. «High Beam Indicator Inoperative»(/chevrolet/cobalt/i-2004-2010/remont/exterior-lights/#lighting-systems__high-beam-indicator-inoperative)
14. «Park Lamps Inoperative»(/chevrolet/cobalt/i-2004-2010/remont/exterior-lights/#lighting-systems__park-lamps-inoperative)
15. «Reading Lamp(s) Inoperative»(/chevrolet/cobalt/i-2004-2010/remont/exterior-lights/#lighting-systems__reading-lamps-inoperative)
16. «Rear Compartment Lamp(s) Inoperative»(/chevrolet/cobalt/i-2004-2010/remont/exterior-lights/#lighting-systems__rear-compartment-lamps-inoperative)
17. «Stop Lamps Inoperative»(/chevrolet/cobalt/i-2004-2010/remont/exterior-lights/#lighting-systems__stop-lamps-inoperative)
18. «Turn Signal Lamps and/or Indicators Inoperative»(/chevrolet/cobalt/i-2004-2010/remont/exterior-lights/#lighting-systems__turn-signal-lamps-andor-indicators-inoperative)

Automatic Lamp Control Inoperative

Automatic Lamp Control 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

Courtesy Lamps Inoperative

Daytime Running Lamps (DRL) Inoperative

Daytime Running Lamps (DRL) Inoperative

Dome Lamps Inoperative

Dome Lamps Inoperative

Fog Lamp Indicator Inoperative

Fog Lamp Indicator Inoperative

Fog Lamps Always On

Fog Lamps Always On

Fog Lamps Inoperative

Fog Lamps Inoperative

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 Inoperative

High Beam Indicator Inoperative

Illuminated Entry Lamps Inoperative

Illuminated Entry Lamps Inoperative

Interior Backlighting Does Not Dim

Interior Backlighting Does Not Dim

Interior Backlighting Inoperative

Interior Backlighting Inoperative

Instrument Panel (I/P) Compartment Lamp Inoperative

Instrument Panel (I/P) Compartment Lamp Inoperative

Park Lamps Inoperative

Park Lamps Inoperative

Reading Lamp(s) Inoperative

Reading Lamp(s) Inoperative

Rear Compartment Lamp(s) Inoperative

Rear Compartment Lamp(s) Inoperative

Stop Lamps Inoperative

Stop Lamps Inoperative

Turn Signal Lamps and/or Indicators Inoperative

Turn Signal Lamps and/or Indicators Inoperative

Vanity Mirror Lamp(s) Inoperative

Vanity Mirror Lamp(s) Inoperative

Stop Lamp Switch Adjustment

1. Remove the accelerator pedal retaining nuts. Move the pedal aside.
2. With the brake pedal fully released, insert the stop lamp switch into the brake pedal bracket until the switch plunge is fully depressed into the barrel.
3. Twist the switch clockwise until the travel stop has been reached.
4. The plunger should extend out of the barrel (1) of the switch approximately 1.0 mm (0.04 in).
5. Install the accelerator pedal to the dash panel. Install the retaining nuts Tighten: Tighten the accelerator pedal retaining nuts to 10 N.m (89 lb in)
6. Inspect the stop lamps for proper operation.

Removal Procedure

1. Remove the accelerator pedal retaining nuts. Move the pedal aside.
2. Remove the stop lamp switch by grasping the switch and turning it counterclockwise while pulling toward the front of the vehicle.
3. Disconnect the stop lamp switch electrical connector.

Installation Procedure

1. Connect the stop lamp switch electrical connector.
2. Insert the stop lamp switch into the retainer.
3. Install the accelerator pedal to the dash panel. Install the retaining nuts. Tighten: Tighten the accelerator pedal retaining nuts to 10 N.m (89 lb in).
4. Adjust the stop lamp switch. Refer to «Stop Lamp Switch Adjustment»(/chevrolet/cobalt/i-2004-2010/remont/exterior-lights/#lighting-systems__stop-lamp-switch-adjustment) .

Scheme 21

Fog Lamp Switch Replacement - Front

Scheme 22

Hazard Warning Switch Replacement

Scheme 23

Instrument Panel (I/P) Dimmer Switch Replacement

Scheme 24

Ambient Light Sensor Replacement

Scheme 25

Reading Lamp Bulb Replacement

Scheme 26

Reading Lamp Replacement

Scheme 27

Trans Floor Shift Control Indicator Lamp Replacement

Dome Lamp Replacement

Dome Lamp Replacement

Scheme 28

Dome Lamp Bulb Replacement

Scheme 29

Headlamp Capsule, Headlamp Housing Bracket & Fog Lamp Replacement

Visual Aiming Preparation Procedure

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

The aiming screen should meet the following criteria

1. The area will consist of a level surface large enough to allow for a vehicle and an additional 7.62 m (25 ft) 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 should be made to align the aiming screen parallel with the vehicle.
3. The screen shall be provided with a fixed vertical centerline, 2 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 a permanent location, 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 left vehicle 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 approximately 75 kg (165 lb) on the driver 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. Raise 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. Block the light from projecting onto the screen from the passenger side headlamp.
9. Adjust the vertical aim screw (1) of the headlamps to the specifications required by the state and the local authorities, or as shown in step number 8.
10. Repeat the aiming procedure for the passenger side headlamp while blocking the light from projecting onto the screen from the driver side headlamp.
11. Turn the headlamps OFF.
12. Close the hood.

Preparation Procedure

1. Completely assemble all of the components on the vehicle.
2. Place the vehicle on a level surface.
3. Stop all unnecessary operations or work that could affect the ride height of the vehicle.
4. Close the doors and verify that the luggage compartment is empty.
5. Stabilize the suspension by rocking the vehicle sideways.
6. Ensure that the fuel level is 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.

Aiming Procedure

1. Park the vehicle 7.6 m (25 ft) away from the target screen.
2. Measure from the center of the fog lamp to the ground line. Using this measurement, mark the horizontal centerline (2) of the fog lamp on the target screen directly in front of the vehicle.
3. The adjustment screw (1) is located in the front fascia just above the fog lamp assembly.
4. Turn ON the fog lamps. The top of the fog lamp beam image (4) on the target screen should be 102 mm (4 in) below the center of the fog lamp lens height.
5. Adjust the fog lamp as required using the adjusting screw (1) on the front of the fog lamp.
6. Turn OFF the fog lamps.

Scheme 30

High Mounted Stop Lamp Replacement

Scheme 31

Cargo Lamp Replacement

1. Remove the license plate from the rear bumper fascia.
2. Remove the screws (1) from the license plate lamp.
3. Remove the license plate lamp (2) from the rear bumper fascia.
4. Remove the bulb/socket from the license plate lamp (2) by turning counterclockwise.
5. Remove the bulb from the socket.

1. Install the bulb to the socket.
2. Install the socket to the license plate lamp (2) by turning the socket clockwise.
3. Install the license plate lamp (2) to the rear bumper fascia.
4. Install the screws (1) to the license plate lamp. Tighten: Tighten the license plate lamp screws to 2 N.m (18 lb in).
5. Install the license plate to the rear bumper fascia.

Scheme 32

Tail Lamp Assembly and /or Backup, Sidemarker, Stop, Turn Signal Bulb Replacement (Chevy Coupe)

Scheme 33

Tail Lamp Assembly and /or Backup, Sidemarker, Stop, Turn Signal Bulb Replacement (Chevy/Pontiac Sedan)

Exterior Lamps

The exterior lighting system consist of the following lamps

1. The headlamps
2. The daytime running lamps
3. The fog lamps
4. The park, tail, and marker lamps
5. The turn signal lamps
6. The stop lamps
7. The backup lamps

Headlamps

The headlamps may be turned ON 2 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 OFF in daylight conditions, or low beam operation in low light conditions. Battery positive voltage is supplied to the low beam relay and the high beam relay in the underhood fuse block. When low beam headlamps are requested, the body control module (BCM) supplies ground to the coil side of the low beam relay. This activates the relay and the relay supplies voltage to the left hand low beam headlamp through the LH LOW BEAM fuse and to the right hand low beam headlamp through the RH LOW BEAM fuse. Ground for the left hand low beam headlamp is provided at G101. Ground for the right hand low beam headlamp is provided at G102. When high beam headlamps are requested, the BCM supplies ground to the coil side of the high beam relay. This activates the relay and the relay supplies voltage to the left hand high beam headlamp through the LH HIGH BEAM fuse and to the right hand high beam headlamp through the RH HIGH BEAM fuse. Ground for the left hand high beam headlamp is provided at G101. Ground for the right hand high beam headlamp is provided at G102.

Daytime Running Lamps (DRL)

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 daytime running lamps (DRL) or the headlights if the headlamp switch is in the AUTO position. Any function or condition that turns ON the headlights will cancel the DRL operation. With the headlight switch in the AUTO position, the headlights will either be turned ON or OFF, after an approximate 30-second delay depending on whether daylight or low light conditions are sensed. The DRL illuminates the park/turn signal and DRL lamps. The DRL will operate when the ignition switch is in the ON position, the gear selector is not in the PARK position, and the parking brake is released. When these conditions have been met and the ambient light sensor indicates daytime conditions, the DRL will illuminate.

DRL operation in manual transmission equipped vehicles will occur when the ignition switch is in the ON position, and the parking brake is released.

Fog Lamps

With the ignition switch in the ON position, and the park lamps or low beam headlights ON, the fog lights will illuminate when the driver presses the fog lamp switch. The FRT FOG fuse in the underhood fuse block supplies battery positive voltage to the switch side of the FRT FOG relay. When the fog lamp switch is pressed, the body control module (BCM) fog lamp switch input is grounded. Ground is provided at G203. The BCM will then energize the FRT FOG relay control circuit. The current flow is now from the FRT FOG relay to both front fog lamps and to ground. Ground is provided at G101 and G102. The state of the fog lamps, either ON or OFF, will remain the same until the fog lamp switch is pressed again, 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.

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 HEADLAMP position, or anytime the headlights are requested. The PARK LAMPS fuse in the rear fuse block supplies battery positive voltage to the PARK LAMP relay switch contacts. The PARK LAMPS fuse in the rear fuse block also supplies battery positive voltage to the PARK LAMP relay coil. When the park lamps are turned ON, the body control module (BCM) energizes the park lamp relay. Current flow is from the PARK LAMP relay to their respective park and marker lamps and to ground. Ground is provided at G101, G102, G401, and G403.

Remote Keyless Entry Exterior Lamp Illumination

On vehicles with a remote control door lock receiver (RCDLR), when the RCDLR module receives a door unlock command from the remote keyless entry (RKE) transmitter, the RCDLR module will send a class 2 message to the body control module (BCM) indicating that an UNLOCK command has been received. The BCM will then flash the park lamps twice. With all the doors closed, and the RKE transmitter is used to lock the doors, the park lamps will flash twice. The park lamps will not flash if the rear compartment is opened using the RKE transmitter.

On vehicles without a RCDLR, when the BCM receives a door unlock command from the RKE transmitter, the BCM will then flash the park lamps twice. With all the doors closed, and the RKE transmitter is used to lock the doors, the park lamps will flash twice. The park lamps will not flash if the rear compartment is opened using the RKE transmitter.

Turn Signal Lamps

The body control module (BCM) is responsible for controlling the turn signals and hazard lamps. When the turn signal switch is placed in either the left turn or right turn position, the BCM receives a signal from the turn signal switch. The BCM then sends an on-off voltage signal to either the left or right turn signals and their instrument panel cluster (IPC) indicator. When the hazard switch is pressed, the BCM receives a signal from the hazard switch. The BCM then will send an on-off voltage signal to all the turn signal lamps. All the turn signal lamps will flash including both IPC turn signal indicators.

Stop Lamps

The body control module (BCM) is responsible for controlling the stop lamps. When the driver presses the brake pedal, the BCM will receive a signal from the brake pedal position sensor. The BCM then supplies battery positive voltage to both left and right stop lamp assemblies and to the center high mounted stop lamp (CHMSL). The stop lamps are grounded at G401 and G403. The CHMSL is grounded at G302.

Backup Lamps

The R-BEC 1 fuse in the underhood fuse block supplies battery positive voltage to the BACKUP LAMP relay through the BACKUP LAMP fuse. When the gear selector is placed in reverse, the body control module (BCM) supplies ground to the BACKUP LAMP relay. This energizes the BACKUP LAMP relay and current flows from the BACKUP LAMP relay to the backup lamps and then to ground. The backup lamps are grounded at G401 and G403.

Inadvertent Power

The body control module (BCM) used in this vehicle controls the lighting system through circuits that enable both the exterior lamp functions of park, head, and fog lamps as well as the interior lamps. The BCM opens these enabling circuits shortly after the ignition switch is turned OFF with no lamp switch activity. If the ignition switch is turned to any position other than OFF, or if a lamp switch is activated during this period, the timer will reset itself again.

Interior Lamps

The interior lamps consist of the following 2 groups. The first group are those lamps which may not be dimmed. The second group includes lamps that may be dimmed.

Courtesy/Illuminated Entry Lamps

This group includes lamps that may be manually turned ON by placing the interior lamp switch in the ON position, or by opening a door.

1. The dome lamp
2. The reading lamps
3. The rearview mirror lamps
4. The vanity mirror lamps

The dome lamp switch has 3 positions: DOOR, OFF, and ON. When in the DOOR position, the dome lamp operation is controlled by the body control module (BCM). The ON position provides a ground for continuous operation. Ground is provided at G302. The OFF position turns OFF any dome lamp operation. The courtesy lamps, may be manually turned ON by placing the instrument panel (I/P) dimmer switch in the DOME position. When the dome lamp switch is in the DOOR position, the dome lamp will illuminate when a door is opened. When a door is opened, the courtesy lamps turn ON. After all the doors have been closed, the courtesy lamps will remain illuminated approximately 10 seconds after the last door closes. When the driver places the dome lamp switch in the OFF position, the dome lamp will be disabled.

The inadvertent power control circuit of the BCM supplies battery positive voltage to the dome lamp, reading lamps, and vanity mirror lamps. When any door is opened, the door jam switch contacts close and the door open input to the BCM is grounded.

If the driver inadvertently leaves any interior lamp ON, the BCM will turn it OFF after 20 minutes.

The courtesy lamps will normally turn OFF using the theater dimming feature. The BCM provides a pulse width modulated ground to the dome lamp for the theater dimming feature. The courtesy lamps will also turn OFF immediately if a door lock command is received with all the doors closed, or if the ignition switch is turned to the ON position.

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 10 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 ON or START position, the courtesy lamps will turn OFF immediately.

On vehicles with a remote control door lock receiver (RCDLR), when the RCDLR module receives a door unlock command from the remote keyless entry (RKE) transmitter, the RCDLR module will send a class 2 message to the BCM indicating that an UNLOCK command has been received. The BCM will keep the courtesy lamps ON approximately 10 seconds and then turn them OFF through the theater dimming feature. If the door locks are activated to the LOCK position, the courtesy lamps will deactivate immediately. When the ignition switch is turned to either the ON or RUN position, the courtesy lamps will deactivate in approximately 1 second.

On vehicles without a RCDLR, when the BCM receives a door unlock command from the RKE transmitter, the BCM will keep the courtesy lamps ON approximately 10 seconds and then turn them OFF through the theater dimming feature. If the door locks are activated to the LOCK position, the courtesy lamps will deactivate immediately. When the ignition switch is turned to either the ON or RUN position, the courtesy lamps will deactivate in approximately 1 second.

Rear Compartment Lamp

The inadvertent power relay also provides battery positive voltage to the rear compartment lamp. When the rear compartment is opened, its switch closes to provide a ground circuit and the rear compartment lamp illuminates. Ground is provided at G401.

Interior Lamps Dimming

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

1. Adjustable pedal position switch
2. Door switches and window switches
3. Fog lamp switch
4. Heated seat switches
5. HVAC control head assembly
6. Hazard switch
7. Outside rearview mirror switch
8. Power sunroof switch assembly
9. Radio
10. Rear compartment lid release switch
11. Rear seat audio module
12. Steering wheel radio controls
13. The instrument panel cluster (IPC)
14. Traction control switch

When the ignition switch is turned to the ON position, the VF displays (radio) turn ON at maximum brightness. When the park lamps are ON and the ambient light sensor indicates low light conditions, all incandescent back lighting turns ON at the dimming level indicated by the instrument panel (I/P) dimmer switch. At the same time all VF displays dim to match the indicated dimming level. The body control module (BCM) is responsible for the dimming of the interior lights. The BCM receives a varying signal from the I/P dimmer switch. Based on the position of the I/P dimmer switch, the BCM then supplies the appropriate amount of voltage to the interior lamps. When the headlight switch is turned to the PARK or HEADLAMP position, all incandescent back lighting turns ON at the dimming level indicated by the I/P dimmer switch. 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 position.

See also:
• Diagnostic System Check - Vehicle
• Testing for Intermittent Conditions and Poor Connections
• Master Electrical Component List
• Circuit Testing
• Wiring Repairs
• Control Module References
• Relay Replacement (Within an Electrical Center)
• Connector Repairs
• Circuit Protection - Circuit Breakers
• Checking Aftermarket Accessories
• Diagnostic Starting Point - Doors
• Circuit Protection - Fusible Links
• Multifunction, Turn Signal Switch Replacement
• Symptoms - Keyless Entry
• Sunshade Replacement
• Fastener Notice
• Steering Column Filler Replacement
• Halogen Bulb Caution
• Interior Lights Schematics
• Backup Lamps Always On
• Backup Lamps Inoperative
• Courtesy Lamps Always On
• Courtesy Lamps Inoperative
• Fog Lamps Always On
• Fog Lamps Inoperative
• 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 Inoperative
• Park Lamps Inoperative
• Reading Lamp(s) Inoperative
• Rear Compartment Lamp(s) Inoperative
• Stop Lamps Inoperative
• Turn Signal Lamps and/or Indicators Inoperative
• Stop Lamp Switch Adjustment
• Fastener Tightening Specifications