Contents Wiring diagrams Section: Exterior Lights All sections

Lighting: Overview Hummer H3 I

Exterior Lights ~1547 words

Test Description

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

  1. 4: This step tests if battery positive voltage is constantly being applied to the supply voltage circuit.
  2. 5: This step tests if a condition exists in the supply voltage circuit.
  3. 6: This step tests if a condition exists in the ground circuit.
  4. 10: After replacement of the IPC, you must calibrate the new cluster for proper operation.
  5. 11: 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 , Displays and Gages Connector End Views or Data Communication Connector End Views
1Did you perform the Diagnostic System Check - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle
2Turn ON the ignition, with the engine OFF. Activate the turn signals. Do the exterior turn signals operate correctly?Go to Step 3Go to Symptoms - Lighting Systems
3Turn OFF the ignition. Remove the instrument panel cluster (IPC). Refer to Instrument Cluster Replacement (Left Hand Drive) or Instrument Cluster Replacement (Right Hand Drive) . Turn ON the ignition, with the engine OFF. Connect a test lamp between the ground circuit and the left turn signal indicator supply voltage circuit at the IPC connector. Activate the inoperative turn signal ON and OFF. Does the test lamp illuminate?Go to Step 4Go to Step 5
4Does the test lamp remain illuminated with each command?Go to Step 7Go to Step 8
5Test for a short to ground, open or high resistance in the left turn signal indicator supply voltage circuit. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 12Go to Step 6
6Test for an open or high resistance in the ground circuit. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 12Go to Step 9
7Test the left turn signal indicator supply voltage circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 12Go to Step 9
8Inspect for poor connections at the IPC. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 12Go to Step 10
9Inspect for poor connections at the harness connector of the body control module (BCM). Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 12Go to Step 11
10Replace the IPC. Refer to Control Module References for replacement, setup and programming. Did you complete the replacement?Go to Step 12
11Replace the BCM. Refer to Control Module References for replacement, setup and programming. Did you complete the replacement?Go to Step 12
12Use 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

DTC B0525 (W/O RPO CW9 )

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

  1. 2: Listen for an audible click when the rear fog lamp relay operates. Command both the ON and OFF states. Repeat the commands as necessary.
  2. 3: This step tests for ground at the coil side of the rear fog lamp relay.
  3. 4: This step verifies that the BCM is providing battery positive voltage to the rear fog lamp relay.
  4. 5: This step tests if battery positive voltage is constantly being applied to the rear fog lamp relay.
  5. 6: This step tests if a condition exists in the rear 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 Data Communication Connector End Views
1Did you perform the Diagnostic System Check - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle
2Install a scan tool. Turn ON the ignition, with the engine OFF. With a scan tool, command the rear fog lamp relay ON and OFF. Does the rear fog lamp relay turn ON and OFF with each command?Go to Testing for Intermittent Conditions and Poor ConnectionsGo to Step 3
3Turn OFF the ignition. Remove the rear fog lamp relay. Refer to Relay Replacement (Attached to Wire Harness) or Relay Replacement (Within an Electrical Center) . Turn ON the ignition, with the engine OFF. Connect a test lamp between the ground circuit of the rear fog lamp relay and the battery positive voltage circuit of the rear fog lamp relay. Does the test lamp illuminate?Go to Step 4Go to Step 10
4Connect a test lamp between the control circuit of the rear fog lamp relay and the ground circuit of the rear fog lamp relay. With a scan tool, command the rear 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 for a short to ground, an open or high resistance in the rear fog lamp relay control circuit and rear fog lamp switch indicator control circuit. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 13Go to Step 9
7Test for a short to voltage in the rear fog lamp relay control circuit and rear fog lamp switch indicator control circuit. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 13Go to Step 9
8Inspect for poor connections at the rear fog lamp relay. Refer to Circuit Testing and Wiring Repairs . 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 . Did you find and correct the condition?Go to Step 13Go to Step 12
10Repair the open or high resistance in the ground circuit of the rear fog lamp relay. Refer to Wiring Repairs . Did you complete the repair?Go to Step 13
11Replace the rear fog lamp relay. Refer to Relay Replacement (Attached to Wire Harness) or Relay Replacement (Within an Electrical Center) . Did you complete the replacement?Go to Step 13
12Replace the BCM. Refer to Control Module References for replacement, setup and programming. 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

DTC B0525 (With RPO CW9)

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

  1. 3: This step tests for supply voltage and ground at the inoperative bulb socket.
  2. 4: This step tests if battery positive voltage is constantly being applied to the supply voltage circuit.
  3. 5: This step tests if a condition exists in the supply voltage circuit.
  4. 6: This step tests if a condition exists in the ground circuit.
  5. 12: After replacement of the instrument panel cluster (IPC), you must calibrate the new cluster for proper operation.
  6. 14: 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 , Displays and Gages Connector End Views or Data Communication Connector End Views
1Did you perform the Diagnostic System Check - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle
2Install a scan tool. Turn ON the ignition, with the engine OFF. With a scan tool, command the inoperative turn signal ON and OFF. Does the inoperative turn signal operate ON and OFF with each command?Go to Testing for Intermittent Conditions and Poor ConnectionsGo to Step 3
3Turn OFF the ignition. Remove the inoperative bulb. Refer to Daytime Running Lamp Bulb Replacement , Tail Lamp Bulb Replacement , Instrument Cluster Replacement (Left Hand Drive) or Instrument Cluster Replacement (Right Hand Drive) . Turn ON the ignition, with the engine OFF. Connect a test lamp between the ground circuit and the supply voltage circuit of the inoperative bulb socket. With a scan tool, command the inoperative turn signal ON and OFF. Does the test lamp illuminate?Go to Step 4Go to Step 5
4Does the test lamp remain illuminated with each command?Go to Step 7Go to Step 8
5Test for a short to ground, open or high resistance in the supply voltage circuit. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 15Go to Step 6
6Test for an open or high resistance in the ground circuit. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 15Go to Step 11
7Test the supply voltage circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 15Go to Step 11
8Does the condition only exist with the turn signal indicator in the instrument panel cluster (IPC)?Go to Step 9Go to Step 10
9Inspect for poor connections at the IPC. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 15Go to Step 12
10Inspect for poor connections at the inoperative bulb socket. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 15Go to Step 13
11Inspect for poor connections at the harness connector of the body control module (BCM). Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 15Go to Step 14
12Replace the IPC. Refer to Control Module References for replacement, setup and programming. Did you complete the replacement?Go to Step 15
13Replace the inoperative bulb. Refer to Daytime Running Lamp Bulb Replacement or Tail Lamp Bulb Replacement . Did you complete the replacement?Go to Step 15
14Replace the BCM. Refer to Control Module References for replacement, setup and programming. Did you complete the replacement?Go to Step 15
15Use 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

DTC B0527, B0528 or B0529

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

  1. 4: This step tests if battery positive voltage is constantly being applied to the supply voltage circuit.
  2. 5: This step tests if a condition exists in the supply voltage circuit.
  3. 6: This step tests if a condition exists in the ground circuit.
  4. 10: After replacement of the IPC, you must calibrate the new cluster for proper operation.
  5. 11: 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 , Displays and Gages Connector End Views or Data Communication Connector End Views
1Did you perform the Diagnostic System Check - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle
2Turn ON the ignition, with the engine OFF. Activate the turn signals. Do the exterior turn signals operate correctly?Go to Step 3Go to Symptoms - Lighting Systems
3Turn OFF the ignition. Remove the instrument panel cluster (IPC). Refer to Instrument Cluster Replacement (Left Hand Drive) or Instrument Cluster Replacement (Right Hand Drive) . Turn ON the ignition, with the engine OFF. Connect a test lamp between the ground circuit and the right turn signal indicator supply voltage circuit at the IPC connector. Activate the inoperative turn signal ON and OFF. Does the test lamp illuminate?Go to Step 4Go to Step 5
4Does the test lamp remain illuminated with each command?Go to Step 7Go to Step 8
5Test for a short to ground, open or high resistance in the right turn signal indicator supply voltage circuit. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 12Go to Step 6
6Test for an open or high resistance in the ground circuit. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 12Go to Step 9
7Test the right turn signal indicator supply voltage circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 12Go to Step 9
8Inspect for poor connections at the IPC. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 12Go to Step 10
9Inspect for poor connections at the harness connector of the body control module (BCM). Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 12Go to Step 11
10Replace the IPC. Refer to Control Module References for replacement, setup and programming. Did you complete the replacement?Go to Step 12
11Replace the BCM. Refer to Control Module References for replacement, setup and programming. Did you complete the replacement?Go to Step 12
12Use 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

DTC B0530 (W/O RPO CW9)

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

  1. 3: This step tests for supply voltage and ground at the inoperative bulb socket.
  2. 4: This step tests if battery positive voltage is constantly being applied to the supply voltage circuit.
  3. 5: This step tests if a condition exists in the supply voltage circuit.
  4. 6: This step tests if a condition exists in the ground circuit.
  5. 12: After replacement of the instrument panel cluster (IPC), you must calibrate the new cluster for proper operation.
  6. 14: 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 , Displays and Gages Connector End Views or Data Communication Connector End Views
1Did you perform the Diagnostic System Check - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle
2Install a scan tool. Turn ON the ignition, with the engine OFF. With a scan tool, command the inoperative turn signal ON and OFF. Does the inoperative turn signal operate ON and OFF with each command?Go to Testing for Intermittent Conditions and Poor ConnectionsGo to Step 3
3Turn OFF the ignition. Remove the inoperative bulb. Refer to Daytime Running Lamp Bulb Replacement , Tail Lamp Bulb Replacement , Instrument Cluster Replacement (Left Hand Drive) or Instrument Cluster Replacement (Right Hand Drive) . Turn ON the ignition, with the engine OFF. Connect a test lamp between the ground circuit and the supply voltage circuit of the inoperative bulb socket. With a scan tool, command the inoperative turn signal ON and OFF. Does the test lamp illuminate?Go to Step 4Go to Step 5
4Does the test lamp remain illuminated with each command?Go to Step 7Go to Step 8
5Test for a short to ground, open or high resistance in the supply voltage circuit. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 15Go to Step 6
6Test for an open or high resistance in the ground circuit. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 15Go to Step 11
7Test the supply voltage circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 15Go to Step 11
8Does the condition only exist with the turn signal indicator in the instrument panel cluster (IPC)?Go to Step 9Go to Step 10
9Inspect for poor connections at the IPC. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 15Go to Step 12
10Inspect for poor connections at the inoperative bulb socket. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 15Go to Step 13
11Inspect for poor connections at the harness connector of the body control module (BCM). Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 15Go to Step 14
12Replace the IPC. Refer to Control Module References for replacement, setup and programming. Did you complete the replacement?Go to Step 15
13Replace the inoperative bulb. Refer To Daytime Running Lamp Bulb Replacement or Tail Lamp Bulb Replacement . Did you complete the replacement?Go to Step 15
14Replace the BCM. Refer to Control Module References for replacement, setup and programming. Did you complete the replacement?Go to Step 15
15Use 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

DTC B0532, B0533 or B0534

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: This step tests for ground at the coil side of the front fog lamp relay.
  3. 4: This step verifies that the BCM is providing battery positive voltage to the front fog lamp relay.
  4. 5: This step tests if battery positive voltage is constantly being applied to the front fog lamp relay.
  5. 6: This step tests if a condition exists 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 Data Communication Connector End Views
1Did you perform the Diagnostic System Check - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle
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 ConnectionsGo to Step 3
3Turn OFF the ignition. Remove the front fog lamp relay. Refer to Relay Replacement (Attached to Wire Harness) or Relay Replacement (Within an Electrical Center) . Turn ON the ignition, with the engine OFF. Connect a test lamp between the ground circuit of the front fog lamp relay and the battery positive voltage circuit of the front fog lamp relay. 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 ground 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 for a short to ground, an open or high resistance in the fog lamp relay control circuit and fog lamp switch indicator control circuit. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 13Go to Step 9
7Test for a short to voltage in the fog lamp relay control circuit and fog lamp switch indicator control circuit. Refer to Circuit Testing and Wiring Repairs . 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 . 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 . Did you find and correct the condition?Go to Step 13Go to Step 12
10Repair the open or high resistance in the ground circuit of the front fog lamp relay. Refer to Wiring Repairs . Did you complete the repair?Go to Step 13
11Replace the front fog lamp relay. Refer to Relay Replacement (Attached to Wire Harness) or Relay Replacement (Within an Electrical Center) . Did you complete the replacement?Go to Step 13
12Replace the BCM. Refer to Control Module References for replacement, setup and programming. 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

DTC B2532 or B2533

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

  1. 2: This step determines if the problem exists in the wiring.
  2. 3: This step determines if a condition exist in the TBC battery voltage supply circuit.
  3. 5: 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 Data Communication Connector End Views
1Did you perform the Diagnostic System Check - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle
2Test the inadvertent power supply voltage circuit for a short to voltage or short to ground. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 6Go to Step 3
3Test the truck body controller (TBC) battery positive supply voltage circuit for a short to ground, open or high resistance. Refer to Circuit Testing . Did you find and correct the condition?Go to Step 6Go to Step 4
4Inspect 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 . Did you find and correct the condition?Go to Step 6Go to Step 5
5Replace the BCM. Refer to Control Module References for replacement, setup and programming. 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

DTC B2557 or B2558

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

  1. 3: This step tests for voltage at the voltage supply side of the headlamp relay.
  2. 4: This step verifies that the BCM is providing ground to the headlamp relay.
  3. 5: This step tests if ground is constantly being applied to the headlamp relay.
  4. 6: This step 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 Data Communication Connector End Views
1Did you perform the Diagnostic System Check - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle
2Install a scan tool. Turn ON the ignition, with the engine OFF. With a scan tool, command the headlamps ON and OFF. Does the headlamp relay turn ON and OFF with each command?Go to Testing for Intermittent Conditions and Poor ConnectionsGo to Step 3
3Turn OFF the ignition. Disconnect the headlamp relay. Turn ON the ignition, with the engine OFF. Probe the battery positive voltage circuit of the 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 headlamp relay and the battery positive voltage circuit of the headlamp relay. With a scan tool, command the headlamps 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 headlamp relay for a short to voltage or an open. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 13Go to Step 9
7Test the control circuit of the headlamp relay for a short to ground. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 13Go to Step 9
8Inspect for poor connections at the headlamp relay. Refer to Circuit Testing and Wiring Repairs . 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 . Did you find and correct the condition?Go to Step 13Go to Step 12
10Repair the battery positive voltage circuit of the headlamp relay. Refer to Wiring Repairs . Did you complete the repair?Go to Step 13
11Replace the headlamp relay. Refer to Relay Replacement (Attached to Wire Harness) or Relay Replacement (Within an Electrical Center) . Did you complete the replacement?Go to Step 13
12Replace the BCM. Refer to Control Module References for replacement, setup and programming. 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

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: This step tests for voltage at the coil side of the high beam relay.
  3. 4: This step verifies that the BCM is providing ground to the high beam relay.
  4. 5: This step tests if ground is constantly being applied to the high beam relay.
  5. 6: This step 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 Data Communication Connector End Views
1Did you perform the Diagnostic System Check - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle
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 ConnectionsGo 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 . 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 . 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 . 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 . 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 . Did you complete the repair?Go to Step 13
11Replace the high beam relay. Refer to Relay Replacement (Attached to Wire Harness) or Relay Replacement (Within an Electrical Center) . Did you complete the replacement?Go to Step 13
12Replace the BCM. Refer to Control Module References for replacement, setup and programming. 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

DTC B2582 or B2583

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: This step tests for voltage at the coil side of the park lamp relay.
  3. 4: This step verifies that the BCM is providing ground to the park lamp relay.
  4. 5: This step tests if ground is constantly being applied to the park lamp relay.
  5. 6: This step 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 Data Communication Connector End Views
1Did you perform the Diagnostic System Check - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle
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 ConnectionsGo 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 . 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 . 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 . 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 . 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 . Did you complete the repair?Go to Step 13
11Replace the park lamp relay. Refer to Relay Replacement (Attached to Wire Harness) or Relay Replacement (Within an Electrical Center) . Did you complete the replacement?Go to Step 13
12Replace the BCM. Refer to Control Module References for replacement, setup and programming. 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

DTC B2585

Circuit/System Description

The daytime running lights (DRL) relay is controlled by the body control module (BCM). Battery positive voltage is applied to the relay coil at all times. The BCM grounds the DRL relay control circuit in order to turn ON the DRL relay illuminating the low beam headlamps at a reduced intensity.

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

  1. 2: This step determines by process of elimination which, if any, dimmable component is causing the DTC to set.
  2. 3: This step 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 Data Communication Connector End Views
1Did you perform the Diagnostic System Check - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle
2Clear the DTC B2622 or B2623 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 instrument panel lamps dimming control circuit, one at a time, while monitoring the scan tool current codes. Does either DTC not reset after a particular dimmable component was disconnected?Go to Step 4Go to Step 3
3Test for one of the following conditions. Refer to Circuit Testing and Wiring Repairs . A short to voltage or short to ground in the I/P lamps supply voltage circuit. An open, high resistance or short to ground in the park lamp supply voltage circuit. 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
5Replace the body control module (BCM). Refer to Control Module References for replacement, setup and programming. 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

DTC B2622 or B2623

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

  1. 3: This step tests for the proper operation of the circuit in the low voltage range.
  2. 4: This step 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 voltage.
  3. 5: This step tests for a short to voltage in the signal circuit.
  4. 6: This step 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 Data Communication Connector End Views
1Did you perform the Diagnostic System Check - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle
2Install a scan tool. Turn ON the ignition, with the engine OFF. With the scan tool, observe the Dimming Potentiometer input data parameter in the body control module (BCM) Data List. Does the scan tool indicate that the Dimming Potentiometer input data parameter is within the specified range?0.6-4.5 VGo to Testing for Intermittent Conditions and Poor ConnectionsGo to Step 3
3Turn OFF the ignition. Disconnect the headlamp and panel dimmer switch. Turn ON the ignition, with the engine OFF. With a scan tool, observe the Dimming Potentiometer input data parameter. Does the scan tool indicate that the Dimming Input data parameter is greater than the specified value?4.5 VGo to Step 10Go to Step 4
4Turn OFF the ignition. Connect a 3-amp fused jumper wire between the connector terminals of the low reference circuit and the signal circuit of the headlamp and panel dimmer switch. Turn ON the ignition, with the engine OFF. With a scan tool, observe the Dimming Potentiometer input data parameter. Does the scan tool indicate that the Dimming Potentiometer input data parameter is less than the specified value?4.86 VGo to Step 5Go to Step 8
5Disconnect the fused jumper wire. Measure the voltage between the connector terminals of the low reference circuit and the signal circuit of the headlamp and panel dimmer 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 headlamp and panel dimmer switch connector and a good ground. Does the resistance measure less than the specified value?5 ohmsGo to Step 12Go to Step 11
7Test the signal circuit of the headlamp and panel dimmer switch for a short to voltage. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 16Go to Step 13
8Test the signal circuit of the headlamp and panel dimmer switch for a open or high resistance. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 16Go to Step 9
9Test the low reference circuit of the headlamp and panel dimmer switch for an open or high resistance. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 16Go to Step 13
10Test the signal circuit of the headlamp and panel dimmer switch for a short to voltage. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 16Go to Step 13
11Disconnect the body control module. Test the low reference circuit of the headlamp and panel dimmer switch for a high resistance or an open. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 16Go to Step 13
12Inspect for poor connections at the harness connector of the headlamp and panel dimmer switch. Refer to Circuit Testing and Wiring Repairs . 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 . Did you find and correct the condition?Go to Step 16Go to Step 15
14Replace the headlamp and panel dimmer switch. Refer to Headlamp Switch Replacement . Did you complete the replacement?Go to Step 16
15Replace the BCM. Refer to Control Module References for replacement, setup and programming. 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

DTC B2624

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

  1. 2: This step verifies that the value displayed is within the specified range.
  2. 3: This step tests for the proper operation of the circuit in the high voltage range.
  3. 4: This step 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 Data Communication Connector End Views
1Did you perform the Diagnostic System Check - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle
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 ConnectionsGo 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 . 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 . 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 . 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 . 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 . 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 . 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
12Replace the BCM. Refer to Control Module References for replacement, setup and programming. 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

DTC B2647 or B2648

IMPORTANTThe following steps must be completed before using the symptom tables.
  1. Perform the «Diagnostic System Check - Vehicle»(ref-266892-S29697290792007100900000) 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 and circuit descriptions that apply to the customer complaint in order to familiarize yourself with the system functions. Refer to the following list: «Exterior Lighting Systems Description and Operation»(ref-266867-S13221229012007100900000) «Interior Lighting Systems Description and Operation»(ref-266867-S03263517042007100900000)

The underhood fuse block supplies battery voltage through the FRT POS fuse to the coil and switch terminals of the FRT POSITION LMP relay located in the underhood fuse block. The underhood fuse block also provides battery voltage to the PARK LP relay coil and switch terminals. When the headlamp switch is turned to the position lamp ON position, a signal is sent to the BCM to ground both the FRT POSITION LMP relay and PARK LP relay control circuits. This energizes the relays, closing the switch contacts and provides battery voltage to the front and rear position lamps. The front position lamps are permanently grounded at G105 and the rear position lamps are grounded at G420. With both power and ground, the position lamps illuminate. If the headlamps are activated by either the headlamp switch or the BCM in Automatic Lamp Control (ALC) mode, just the front position lamps will be disabled.