Contents Wiring diagrams Section: Exterior Lights All sections

Lighting Systems: Overview Chevrolet SSR I

Exterior Lights ~1132 words

Test Description

The numbers below refer to the step numbers 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.
StepActionYesNo
1Install a scan tool. Does the scan tool power up?Go to Step 2Go to Scan Tool Does Not Power Up in Data Link Communications
2Turn ON the ignition, with the engine OFF. Attempt to establish communication with the body control module (BCM). Does the scan tool communicate with the BCM?Go to Step 3Go to Scan Tool Does Not Communicate with Class 2 Device in Data Link Communications
3IMPORTANT: The engine may start during the following step. Turn OFF the engine as soon as you have observed the Crank power mode. Access the Class 2 Power Mode in the Diagnostic Circuit Check on the scan tool. Rotate the ignition switch through all positions while observing the Class 2 Power Mode on the Scan Tool. Refer to the Serial Data Power Mode table within Body Control System Description and Operation in Body Control System for a list of the power mode states that correspond to each ignition switch position. Does the ignition switch parameter reading match the ignition switch position for OFF, RUN, and CRANK?Go to Step 4Go to Power Mode Mismatch in Body Control System
4Select the BCM display DTCs function on the scan tool. Does the scan tool display any DTCs?Go to Step 5Go to Symptoms - Lighting Systems
5Does the scan tool display any DTCs which begin with a U ?Go to Scan Tool Does Not Communicate with Class 2 Device in Data Link CommunicationsGo to Step 6
6Does the scan tool display DTC B1000, B1001, B1004, B1007, B1009, B1420, B1440, or C0550?Go to Diagnostic Trouble Code (DTC) List in Body Control SystemGo to Diagnostic Trouble Code (DTC) List
IMPORTANT
The engine may start during the following step. Turn OFF the engine as soon as you have observed the Crank power mode.

Diagnostic System Check - Lighting Systems

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

  1. 2: This step test determines if an open or short to ground exists.
  2. 3: This step test determines if a short to ground exists in the lamp wiring or internally within the BCM.
  3. 4: This step test determines if an open exists in the TBC 4 battery positive voltage circuit, the inadvertent power supply voltage circuit, or internally within the BCM.
  4. 6: After replacement of the BCM you must calibrate the new module for proper operation.
StepActionYesNo
Schematic Reference: Interior Lights Schematics Connector End View Reference: Lighting Systems Connector End Views or Body Control System Connector End Views in Body Control System
1Did you perform the Lighting System Diagnostic System Check?Go to Step 2Go to Diagnostic System Check - Lighting Systems
2Inspect the TBC 4 fuse in the rear fuse block. Is the fuse good?Go to Step 4Go to Step 3
3Test the TBC 4 battery positive voltage and inadvertent power supply voltage circuits for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 7Go to Step 5
4Test the TBC 4 battery positive voltage and inadvertent power supply voltage circuits for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 7Go to Step 5
5Inspect for poor connections at the harness connectors of the body control module (BCM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 7Go to Step 6
6IMPORTANT: Perform the setup procedure for the BCM. Replace the BCM. Refer to Body Control Module Replacement in Body Control System.Did you complete the replacement?Go to Step 7
7Use the scan tool in order to clear the DTCs. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text. Does the DTC reset?Go to Step 2System OK
IMPORTANT
Perform the setup procedure for the BCM.

DTC B1480

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

  1. 2: Listen for an audible click when the front fog lamp relay operates. Command both the ON and OFF states. Repeat the commands as necessary.
  2. 3: Tests for voltage at the coil side of the front fog lamp relay.
  3. 4: Verifies that the BCM is providing ground to the front fog lamp relay.
  4. 5: Tests if ground is constantly being applied to the front fog lamp relay.
  5. 6: Tests if there is opposing voltage present or an open in the front fog lamp relay control circuit.
  6. 12: After replacement of the BCM you must calibrate the new module for proper operation.
StepActionYesNo
Schematic Reference: Fog Lights Schematics Connector End View Reference: Lighting Systems Connector End Views or Body Control System Connector End Views in Body Control System
1Did you perform the Lighting Systems Diagnostic System Check?Go to Step 2Go to Diagnostic System Check - Lighting Systems
2Install a scan tool. Turn ON the ignition, with the engine OFF. With a scan tool, command the front fog lamp relay ON and OFF. Does the front fog lamp relay turn ON and OFF with each command?Go to Testing for Intermittent Conditions and Poor Connections in Wiring SystemsGo to Step 3
3Turn OFF the ignition. Disconnect the front fog lamp relay. Turn ON the ignition, with the engine OFF. Probe the battery positive voltage circuit of the front fog lamp relay with a test lamp that is connected to a good ground. Does the test lamp illuminate?Go to Step 4Go to Step 10
4Connect a test lamp between the control circuit of the front fog lamp relay and the battery positive voltage circuit of the front fog lamp relay. With a scan tool, command the front fog lamp relay ON and OFF. Does the test lamp turn ON and OFF with each command?Go to Step 8Go to Step 5
5Does the test lamp remain illuminated with each command?Go to Step 7Go to Step 6
6Test the control circuit of the front fog lamp relay for a short to voltage or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 13Go to Step 9
7Test the control circuit of the front fog lamp relay for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 13Go to Step 9
8Inspect for poor connections at the front fog lamp relay. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 13Go to Step 11
9Inspect for poor connections at the harness connector of the body control module (BCM). Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 13Go to Step 12
10Repair the battery positive voltage circuit of the front fog lamp relay. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair?Go to Step 13
11Replace the front fog lamp relay. Refer to Relay Replacement (Within an Electrical Center) or Relay Replacement (Attached to Wire Harness) in Wiring Systems. Did you complete the replacement?Go to Step 13
12IMPORTANT: Perform the setup procedure for the BCM. Replace the BCM. Refer to Body Control Module Replacement in Body Control System.Did you complete the replacement?Go to Step 13
13Use the scan tool in order to clear the DTCs. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text. Does the DTC reset?Go to Step 2System OK
IMPORTANT
Perform the setup procedure for the BCM.

DTC B2530

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

  1. 2: This step test determines if the problem exists in the wiring or the BCM.
  2. 3: Inspects for poor connections before a component is replaced.
  3. 4: After replacement of the BCM you must calibrate the new module for proper operation.
StepActionYesNo
Schematic Reference: Exterior Lights Schematics Connector End View Reference: Lighting Systems Connector End Views or Body Control System Connector End Views in Body Control System
1Did you perform the Lighting System Diagnostic System Check?Go to Step 2Go to Diagnostic System Check - Lighting Systems
2Test the following circuits as indicated. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. The TBC 2 battery positive supply voltage circuit and backup lamp voltage supply circuit for an open, high resistance, short to voltage or short to ground. The backup lamp ground circuit for an open or high resistance. Did you find and correct the condition?Go to Step 5Go to Step 3
3Inspect for poor connections at the harness connector of the body control module (BCM). Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 5Go to Step 4
4IMPORTANT: Perform the setup procedure for the BCM. Replace the BCM. Refer to Body Control Module Replacement in Body Control System.Did you complete the replacement?Go to Step 5
5Use the scan tool in order to clear the DTCs. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text. Does the DTC reset?Go to Step 2System OK
IMPORTANT
Perform the setup procedure for the BCM.

DTC B2550

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

  1. 3: Tests for voltage at the voltage supply side of the low beam headlamp relay.
  2. 4: Verifies that the BCM is providing ground to the low beam headlamp relay.
  3. 5: Tests if ground is constantly being applied to the low beam headlamp relay.
  4. 6: Tests if there is opposing voltage present or an open low beam headlamp relay control circuit.
  5. 12: After replacement of the BCM you must calibrate the new module for proper operation.
StepActionYesNo
Schematic Reference: Headlights/Daytime Running Lights (DRL) Schematics Connector End View Reference: Lighting Systems Connector End Views or Body Control System Connector End Views in Body Control System
1Did you perform the Lighting Systems Diagnostic System Check?Go to Step 2Go to Diagnostic System Check - Lighting Systems
2Install a scan tool. Turn ON the ignition, with the engine OFF. With a scan tool, command the low beams ON and OFF. Does the low beam headlamp relay turn ON and OFF with each command?Go to Testing for Intermittent Conditions and Poor Connections in Wiring SystemsGo to Step 3
3Turn OFF the ignition. Disconnect the low beam headlamp relay. Turn ON the ignition, with the engine OFF. Probe the battery positive voltage circuit of the low beam headlamp relay with a test lamp that is connected to a good ground. Does the test lamp illuminate?Go to Step 4Go to Step 10
4Connect a test lamp between the control circuit of the low beam headlamp relay and the battery positive voltage circuit of the low beam headlamp relay. With a scan tool, command the low beam headlamp relay ON and OFF. Does the test lamp turn ON and OFF with each command?Go to Step 8Go to Step 5
5Does the test lamp remain illuminated with each command?Go to Step 7Go to Step 6
6Test the control circuit of the low beam headlamp relay for a short to voltage or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 13Go to Step 9
7Test the control circuit of the low beam headlamp relay for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 13Go to Step 9
8Inspect for poor connections at the low beam headlamp relay. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 13Go to Step 11
9Inspect for poor connections at the harness connector of the body control module (BCM). Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 13Go to Step 12
10Repair the battery positive voltage circuit of the low beam headlamp relay. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair?Go to Step 13
11Replace the low beam headlamp relay. Refer to Relay Replacement (Within an Electrical Center) or Relay Replacement (Attached to Wire Harness) in Wiring Systems. Did you complete the replacement?Go to Step 13
12IMPORTANT: Perform the setup procedure for the BCM. Replace the BCM. Refer to Body Control Module Replacement in Body Control System.Did you complete the replacement?Go to Step 13
13Use the scan tool in order to clear the DTCs. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text. Does the DTC reset?Go to Step 2System OK
IMPORTANT
Perform the setup procedure for the BCM.

DTC B2575

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 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.
StepActionYesNo
Schematic Reference: Headlights/Daytime Running Lights (DRL) Schematics Connector End View Reference: Lighting Systems Connector End Views or Body Control System Connector End Views in Body Control System
1Did you perform the Lighting Systems Diagnostic System Check?Go to Step 2Go to Diagnostic System Check - Lighting Systems
2Install a scan tool. Turn ON the ignition, with the engine OFF. With a scan tool, command the high beam relay ON and OFF. Does the high beam relay turn ON and OFF with each command?Go to Testing for Intermittent Conditions and Poor Connections in Wiring SystemsGo to Step 3
3Turn OFF the ignition. Disconnect the high beam relay. Turn ON the ignition, with the engine OFF. Probe the battery positive voltage circuit of the high beam relay with a test lamp that is connected to a good ground. Does the test lamp illuminate?Go to Step 4Go to Step 10
4Connect a test lamp between the control circuit of the high beam relay and the battery positive voltage circuit of the high beam relay. With a scan tool, command the high beam relay ON and OFF. Does the test lamp turn ON and OFF with each command?Go to Step 8Go to Step 5
5Does the test lamp remain illuminated with each command?Go to Step 7Go to Step 6
6Test the control circuit of the high beam relay for a short to voltage or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 13Go to Step 9
7Test the control circuit of the high beam relay for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 13Go to Step 9
8Inspect for poor connections at the high beam relay. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 13Go to Step 11
9Inspect for poor connections at the harness connector of the body control module (BCM). Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 13Go to Step 12
10Repair the battery positive voltage circuit of the high beam relay. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair?Go to Step 13
11Replace the high beam relay. Refer to Relay Replacement (Within an Electrical Center) or Relay Replacement (Attached to Wire Harness) in Wiring Systems. Did you complete the replacement?Go to Step 13
12IMPORTANT: Perform the setup procedure for the BCM. Replace the BCM. Refer to Body Control Module Replacement in Body Control System.Did you complete the replacement?Go to Step 13
13Use the scan tool in order to clear the DTCs. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text. Does the DTC reset?Go to Step 2System OK
IMPORTANT
Perform the setup procedure for the BCM.

DTC B2580

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 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.
StepActionYesNo
Schematic Reference: Exterior Lights Schematics Connector End View Reference: Lighting Systems Connector End Views or Body Control System Connector End Views in Body Control System
1Did you perform the Lighting Systems Diagnostic System Check?Go to Step 2Go to Diagnostic System Check - Lighting Systems
2Install a scan tool. Turn ON the ignition, with the engine OFF. With a scan tool, command the park lamp relay ON and OFF. Does the park lamp relay turn ON and OFF with each command?Go to Testing for Intermittent Conditions and Poor Connections in Wiring SystemsGo to Step 3
3Turn OFF the ignition. Disconnect the park lamp relay. Turn ON the ignition, with the engine OFF. Probe the battery positive voltage circuit of the park lamp relay with a test lamp that is connected to a good ground. Does the test lamp illuminate?Go to Step 4Go to Step 10
4Connect a test lamp between the control circuit of the park lamp relay and the battery positive voltage circuit of the park lamp relay. With a scan tool, command the park lamp relay ON and OFF. Does the test lamp turn ON and OFF with each command?Go to Step 8Go to Step 5
5Does the test lamp remain illuminated with each command?Go to Step 7Go to Step 6
6Test the control circuit of the park lamp relay for a short to voltage or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 13Go to Step 9
7Test the control circuit of the park lamp relay for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 13Go to Step 9
8Inspect for poor connections at the park lamp relay. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 13Go to Step 11
9Inspect for poor connections at the harness connector of the body control module (BCM). Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 13Go to Step 12
10Repair the battery positive voltage circuit of the park lamp relay. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair?Go to Step 13
11Replace the park lamp relay. Refer to Relay Replacement (Within an Electrical Center) or Relay Replacement (Attached to Wire Harness) in Wiring Systems. Did you complete the replacement?Go to Step 13
12IMPORTANT: Perform the setup procedure for the BCM. Replace the BCM. Refer to Body Control Module Replacement in Body Control System.Did you complete the replacement?Go to Step 13
13Use the scan tool in order to clear the DTCs. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text. Does the DTC reset?Go to Step 2System OK
IMPORTANT
Perform the setup procedure for the BCM.

DTC B2585

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

  1. 2: Listen for an audible click when the DRL relays operate. Command both the ON and OFF states. Repeat the commands as necessary.
  2. 3: Tests for voltage at the coil side of the DRL relays.
  3. 4: Verifies that the BCM is providing ground to the DRL relays.
  4. 5: Tests if ground is constantly being applied to the DRL relays.
  5. 6: Tests if there is opposing voltage present or an open in the DRL relay control circuits.
  6. 12: After replacement of the BCM you must calibrate the new module for proper operation.
StepActionYesNo
Schematic Reference: Headlights/Daytime Running Lights (DRL) Schematics Connector End View Reference: Lighting Systems Connector End Views or Body Control System Connector End Views in Body Control System.
1Did you perform the Lighting Systems Diagnostic System Check?Go to Step 2Go to Diagnostic System Check - Lighting Systems
2Install a scan tool. Turn ON the ignition, with the engine OFF. With a scan tool, command the DRL relays ON and OFF. Do the DRL relays turn ON and OFF with each command?Go to Testing for Intermittent Conditions and Poor Connections in Wiring SystemsGo to Step 3
3Turn OFF the ignition. Disconnect the daytime running lamp (DRL) relays. Turn ON the ignition, with the engine OFF. Connect a test lamp between the battery positive voltage circuit of each of the DRL relays and a good ground. Does the test lamp illuminate?Go to Step 4Go to Step 10
4Connect a test lamp between the control circuit and the battery positive voltage circuit of each of the DRL relays. With a scan tool, command the DRL relays ON and OFF. Does the test lamp turn ON and OFF with each command?Go to Step 8Go to Step 5
5Does the test lamp remain illuminated with each command?Go to Step 7Go to Step 6
6Test the control circuits of the DRL relays for high resistance, an open, a short to voltage or a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 13Go to Step 9
7Test the control circuits of the DRL relays for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 13Go to Step 9
8Inspect for poor connections at the inoperable DRL relay. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 13Go to Step 11
9Inspect for poor connections at the harness connector of the body control module (BCM). Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 13Go to Step 12
10Repair the short to ground, open, or high resistance in one of the following circuits. Refer to Wiring Repairs in Wiring Systems. Battery positive supply voltage DRL diode supply voltage Right headlamp low beam supply Left headlamp low beam supply Did you complete the repair?Go to Step 13
11Replace the inoperable DRL relay. Refer to Relay Replacement (Within an Electrical Center) or Relay Replacement (Attached to Wire Harness) in Wiring Systems. Did you complete the replacement?Go to Step 13
12IMPORTANT: Perform the setup procedure for the BCM. Replace the BCM. Refer to Body Control Module Replacement in Body Control System.Did you complete the replacement?Go to Step 13
13Use the scan tool in order to clear the DTCs. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text. Does the DTC reset?Go to Step 2System OK
IMPORTANT
Perform the setup procedure for the BCM.

DTC B2600

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

  1. 2: This step test determines by process of elimination which, if any, dimmable component is causing the DTC to set.
  2. 3: This step test determines if the problem exists in the wiring or the BCM.
  3. 5: After replacement of the BCM you must calibrate the new module for proper operation.
StepActionYesNo
Schematic Reference: Interior Lights Dimming Schematics Connector End View Reference: Lighting Systems Connector End Views or Body Control System Connector End Views in Body Control System
1Did you perform the Lighting System Diagnostic System Check?Go to Step 2Go to Diagnostic System Check - Lighting Systems
2Clear the DTC B2610 with the scan tool. Turn the park lamps ON. Adjust the instrument panel (I/P) dimmer switch to a mid-range dimming position. Disconnect each dimmable component from the I/P lamps dimming control circuit, one at a time, while monitoring the scan tool current codes. Does DTC B2610 not reset after a particular dimmable component was disconnected?Go to Step 4Go to Step 3
3Test the I/P lamps dimming control circuit for an open, high resistance, short to voltage or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 6Go to Step 5
4Replace the dimmable component associated with when the code did not reset. Refer to the proper replacement procedure for that particular component. Did you complete the repair?Go to Step 6
5IMPORTANT: Perform the setup procedure for the body control module (BCM). Replace the BCM. Refer to Body Control Module Replacement in Body Control System.Did you complete the replacement?Go to Step 6
6Use the scan tool in order to clear the DTCs. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text. Does the DTC reset?Go to Step 2System OK
IMPORTANT
Perform the setup procedure for the body control module (BCM).

DTC B2610

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

  1. 2: This step test determines if an open or short to ground exists.
  2. 3: This step test determines if a short to ground exists in the lamp wiring or internally within the BCM.
  3. 4: This step test determines if an open exists in the TBC 3 battery positive voltage circuit, the courtesy lamp supply voltage circuit, or internally within the BCM.
  4. 6: After replacement of the BCM you must calibrate the new module for proper operation.
StepActionYesNo
Schematic Reference: Interior Lights Schematics Connector End View Reference: Lighting Systems Connector End Views or Body Control System Connector End Views in Body Control System
1Did you perform the Lighting System Diagnostic System Check?Go to Step 2Go to Diagnostic System Check - Lighting Systems
2Inspect the TBC 3 fuse in the rear fuse block. Is the fuse good?Go to Step 4Go to Step 3
3Test the TBC 3 battery positive voltage and courtesy lamp supply voltage circuits for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 7Go to Step 5
4Test the TBC 3 battery positive voltage and courtesy lamp supply voltage circuits for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 7Go to Step 5
5Inspect for poor connections at the harness connectors of the body control module (BCM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 7Go to Step 6
6IMPORTANT: Perform the setup procedure for the BCM. Replace the BCM. Refer to Body Control Module Replacement in Body Control System.Did you complete the replacement?Go to Step 7
7Use the scan tool in order to clear the DTCs. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text. Does the DTC reset?Go to Step 2System OK
IMPORTANT
Perform the setup procedure for the BCM.

DTC B2615

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.
StepActionValue(s)YesNo
Schematic Reference: Interior Lights Dimming Schematics Connector End View Reference: Lighting Systems Connector End Views or Body Control System Connector End Views in Body Control System
1Did you perform the Lighting Systems Diagnostic System Check?Go to Step 2Go to Diagnostic System Check - Lighting Systems
2Install a scan tool. Turn ON the ignition, with the engine OFF. With the scan tool, observe the Dimming Input data parameter in the Body Control Module Data List. Does the scan tool indicate that the Dimming Input data parameter is within the specified range?4.5-5.5 VGo to Testing for Intermittent Conditions and Poor Connections in Wiring SystemsGo to Step 3
3Turn OFF the ignition. Disconnect the headlamp switch. Turn ON the ignition, with the engine OFF. With a scan tool, observe the Dimming Input data parameter. Does the scan tool indicate that the Dimming Input data parameter is less than the specified value?4.5 VGo to Step 4Go to Step 10
4Turn OFF the ignition. Connect a 3-amp fused jumper wire between the 5-volt reference circuit of the instrument panel (I/P) dimmer/headlamp switch and the signal circuit of the I/P dimmer/headlamp switch. Turn ON the ignition, with the engine OFF. With a scan tool, observe the Dimming Input data parameter. Does the scan tool indicate that the Dimming Input data parameter is greater than the specified value?4.86 VGo to Step 5Go to Step 8
5Disconnect the fused jumper wire. Measure the voltage between the 5-volt reference circuit of the I/P dimmer/headlamp switch and the low reference circuit of the I/P dimmer/headlamp switch. Does the voltage measure less than the specified value?5.15 VGo to Step 6Go to Step 7
6Turn OFF the ignition. Disconnect the negative battery cable. Measure the resistance from the low reference circuit of the I/P dimmer/headlamp switch to a good ground. Does the resistance measure less than the specified value?5 ohmsGo to Step 12Go to Step 11
7Test the 5-volt reference circuit of the I/P dimmer/headlamp switch for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 16Go to Step 13
8Test the 5-volt reference circuit of the I/P dimmer/headlamp switch for a short to ground, a high resistance, or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 16Go to Step 9
9Test the signal circuit of the I/P dimmer/headlamp switch for a short to ground, a high resistance, or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 16Go to Step 13
10Test the signal circuit of the I/P dimmer/headlamp switch for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 16Go to Step 13
11Disconnect the body control module (BCM). Test the low reference circuit of the I/P dimmer/headlamp switch for a high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 16Go to Step 13
12Inspect for poor connections at the harness connector of the I/P dimmer/headlamp switch. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 16Go to Step 14
13Inspect for poor connections at the harness connector of the BCM. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 16Go to Step 15
14Replace the headlamp switch. Refer to Headlamp Switch Replacement . Did you complete the replacement?Go to Step 16
15IMPORTANT: Perform the setup procedure for the BCM. Replace the BCM. Refer to Body Control Module Replacement in Body Control System.Did you complete the replacement?Go to Step 16
16Use the scan tool in order to clear the DTCs. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text. Does the DTC reset?Go to Step 2System OK
IMPORTANT
Perform the setup procedure for the BCM.

DTC B2620

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

  1. 2: Verifies that the value displayed is within the specified range.
  2. 3: Tests for the proper operation of the circuit in the high voltage range.
  3. 4: Tests for the proper operation of the circuit in the low voltage range. If the fuse in the jumper opens when you perform this test, the signal circuit is shorted to voltage.
StepActionValue(s)YesNo
Schematic Reference: Headlights/Daytime Running Lights (DRL) Schematics Connector End View Reference: Lighting Systems Connector End Views or Body Control System Connector End Views in Body Control System
1Did you perform the Lighting Systems Diagnostic System Check?Go to Step 2Go to Diagnostic System Check - Lighting Systems
2Install a scan tool. Turn ON the ignition, with the engine OFF. With a scan tool, observe the ambient light sensor parameter in the body control module (BCM) data list. Does the scan tool indicate that the ambient light sensor parameter is within the specified range?1.75-4.9 VGo to Testing for Intermittent Conditions and Poor Connections in Wiring SystemsGo to Step 3
3Turn OFF the ignition. Disconnect the ambient light sensor. Turn ON the ignition, with the engine OFF. With a scan tool, observe the ambient light sensor parameter. Does the scan tool indicate that the ambient light sensor parameter is greater than the specified value?4.9 VGo to Step 4Go to Step 5
4Turn OFF the ignition. Connect a 3-amp fused jumper wire between the ambient light sensor low reference circuit and the ambient light sensor signal circuit at the ambient light sensor harness connector. Turn ON the ignition, with the engine OFF. With a scan tool, observe the ambient light sensor parameter. Does the scan tool indicate that the ambient light sensor parameter is less than the specified value?1.75 VGo to Step 6Go to Step 7
5Test the ambient light sensor signal circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 13Go to Step 10
6Test the ambient light sensor low reference circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 13Go to Step 9
7Test the ambient light sensor signal circuit for a short to voltage, a high resistance, or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 13Go to Step 8
8Test the ambient light sensor low reference circuit for a short to voltage, a high resistance, or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 13Go to Step 10
9Inspect for poor connections at the harness connector of the ambient light sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 13Go to Step 11
10Inspect for poor connections at the harness connector of the BCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 13Go to Step 12
11Replace the ambient light sensor. Refer to Ambient Light Sensor Replacement . Did you complete the replacement?Go to Step 13
12IMPORTANT: Perform the setup procedure for the BCM. Replace the BCM. Refer to Body Control Module Replacement in Body Control System.Did you complete the replacement?Go to Step 13
13Use the scan tool in order to clear the DTCs. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text. Does the DTC reset?Go to Step 2System OK
IMPORTANT
Perform the setup procedure for the BCM.

DTC B2645