Diagnostic Test

CHECK FOR ACTIVE DIAGNOSTIC TROUBLE CODE (DTC)
1. Turn the ignition on.
2. With the scan tool, read DTCs.
  Does the scan tool display this DTC as active?
  
  Yes
  - Go To 2
  No
  - Test complete. The condition or conditions that originally set this DTC are not present at this time. Using the wiring diagrams as a guide, check all related splices and connectors for signs of water intrusion, corrosion, pushed out or bent terminals, and correct pin tension.
  - Perform the BODY VERIFICATION TEST. Refer to STANDARD PROCEDURE .
CHECK THE (L107) PARK LAMP SWITCH SENSE CIRCUIT FOR A SHORT TO VOLTAGE
1. Turn the ignition off.
2. Disconnect the Left Multifunction Switch harness connector.
3. Turn the ignition on.
4. Measure the voltage on the (L107) Park Lamp Switch Sense circuit at the Left Multifunction Switch harness connector.
  Is there any voltage present?
  
  Yes
  - Repair the short to voltage in the (L107) Park Lamp Switch Sense circuit.
  - Perform the BODY VERIFICATION TEST. Refer to STANDARD PROCEDURE .
  No
  - Go To 3
CHECK THE (L107) PARK LAMP SWITCH SENSE CIRCUIT FOR AN OPEN
1. Turn the ignition off.
2. Disconnect the BCM C8 harness connector.
3. Measure the resistance of the (L107) Park Lamp Switch Sense circuit between the Left Multifunction Switch harness connector and the BCM C8 harness connector.
  Is the resistance below 3.0 Ohms?
  
  Yes
  - Go To 4
  No
  - Repair the open in the (L107) Park Lamp Switch Sense circuit.
  - Perform the BODY VERIFICATION TEST. Refer to STANDARD PROCEDURE .
CHECK THE (Z407) GROUND CIRCUIT FOR AN OPEN
1. Measure the resistance of the (Z407) Ground circuit between the Left Multifunction Switch harness connector and the BCM C8 harness connector.
  Is the resistance below 3.0 Ohms?
  
  Yes
  - Go To 5
  No
  - Repair the open in the (Z407) Ground circuit.
  - Perform the BODY VERIFICATION TEST. Refer to STANDARD PROCEDURE .
CHECK THE BCM FOR CORRECT OPERATION
1. Turn the ignition off.
2. Connect the BCM C8 harness connector.
3. Connect a jumper wire between the (L107) Park Lamp Switch Sense circuit and the (Z407) Ground circuit at the Left Multifunction Switch harness connector.
4. Turn the ignition on.
5. With the scan tool, view the Headlamp Switch Position in BCM Data.
  Does the Headlamp Switch Position display On?
  
  Yes
  - Replace the Left Multifunction Switch in accordance with the Service Information. Refer to SWITCH, MULTIFUNCTION, LEFT, REMOVAL .
  - Perform the BODY VERIFICATION TEST. Refer to STANDARD PROCEDURE .
  No
  - Replace the Body Control Module (BCM) in accordance with the Service Information. Refer to MODULE, BODY CONTROL, REMOVAL .
  - Perform the BODY VERIFICATION TEST. Refer to STANDARD PROCEDURE .