Diagnostic Test

CHECK FOR AN 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 appropriate SYSTEM 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 BODY VERIFICATION TEST .
CHECK THE HEADLAMP SWITCH FOR AN INTERNAL SHORT
1. Turn the ignition off.
2. Disconnect the Headlamp Switch harness connector.
3. Turn the ignition on.
4. With the scan tool, erase DTCs.
5. Turn the ignition off and wait 30 seconds.
6. Turn the ignition on.
7. With the scan tool, read DTCs.
  Does the DTC return?
  
  Yes
  - Go To 3
  No
  - Replace the Headlamp Switch in accordance with the Service Information. Refer to SWITCH, MULTIFUNCTION, LEFT, REMOVAL .
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
CHECK THE (L107) PARK LAMP SWITCH SENSE CIRCUIT FOR VOLTAGE
1. Measure the voltage on the (L107) Park Lamps Switch Sense circuit at the Headlamp Switch harness connector.
  Is there any voltage present?
  
  Yes
  - Go To 4
  No
  - Go To 5
CHECK THE (L107) PARK LAMP SWITCH SENSE CIRCUIT FOR A SHORT TO VOLTAGE
1. Turn the ignition off.
2. Disconnect the BCM C8 harness connector.
3. Turn the ignition on.
4. Measure the voltage on the (L107) Park Lamps Switch Sense circuit at the Headlamp Switch harness connector.
  Is there any voltage present?
  
  Yes
  - Repair the (L107) Park Lamps Switch Sense circuit for a short to voltage.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - Replace Body Control Module (BCM) in accordance with the Service Information. Refer to MODULE, BODY CONTROL (BCM), REMOVAL .
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
CHECK THE (L107) PARK LAMP SWITCH SENSE CIRCUIT FOR AN OPEN
1. Disconnect the BCM C8 harness connector.
2. Measure the resistance of the (L107) Park Lamps Switch Sense circuit between the Headlamp Switch harness connector and the BCM C8 harness connector.
  Is the resistance below 3.0 Ohms?
  
  Yes
  - Replace the Headlamp Switch in accordance with the Service Information. Refer to SWITCH, MULTIFUNCTION, LEFT, REMOVAL .
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - Repair the open in the (L107) Park Lamps Switch Sense circuit.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .