Diagnostic Test

CHECK FOR AN ACTIVE DTC
1. With the scan tool, read Body Control Module (BCM) DTCs and record on the repair order.
2. Record the Environmental Data.
3. With the scan tool, erase DTCs.
4. Using the recorded Environmental Data, along with the When Monitored and Set Conditions above, operate the vehicle in the conditions that set the DTC.
5. With the scan tool, read BCM DTCs.
  Did the DTC return?
  
  Yes
  - Go To 2
  No
  - Perform the TESTING FOR INTERMITTENT CONDITIONS procedure. Refer to TESTING FOR AN INTERMITTENT CONDITION .
CHECK THE (L307) HEADLAMP SWITCH MUX CIRCUIT FOR A SHORT TO VOLTAGE
1. Turn the ignition off.
2. Disconnect the Headlamp Switch harness connector.
3. Turn the ignition on.
4. Measure the voltage on the (L307) Headlamp Switch MUX circuit at the Headlamp Switch harness connector.
  Is the voltage above 5.2 volts?
  
  Yes
  - Repair the short to voltage on the (L307) Headlamp Switch MUX circuit.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - Go To 3
CHECK THE (L900) HEADLAMP SWITCH MUX RETURN CIRCUIT FOR AN OPEN
1. Turn the ignition off.
2. Disconnect the BCM C8/H harness connector.
3. Measure the resistance of the (L900) Headlamp Switch MUX Return circuit between the Headlamp Switch harness connector and PIN 51 in the BCM C8/H harness connector.
  Is the resistance above 3.0 Ohms?
  
  Yes
  - Repair the open in the (L900) Headlamp Switch MUX Return circuit.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - Go To 4
CHECK THE (L307) HEADLAMP SWITCH MUX CIRCUIT FOR AN OPEN
1. Measure the resistance of the (L307) Headlamp Switch MUX circuit between the Headlamp Switch harness connector and PIN 42 in the BCM C8/H harness connector.
  Is the resistance above 3.0 Ohms?
  
  Yes
  - Repair the open in the (L307) Headlamp Switch MUX circuit.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - Go To 5
CHECK THE (L307) HEADLAMP SWITCH MUX CIRCUIT FOR A SHORT TO GROUND
1. Check for continuity between ground and the (L307) Headlamp Switch MUX circuit at the Headlamp Switch harness connector.
  Is there continuity between ground and the (L307) Headlamp Switch MUX circuit?
  
  Yes
  - Repair the short to ground in the (L307) Headlamp Switch MUX circuit.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - Replace the Headlamp Switch in accordance with the Service Information. Refer to SWITCH, HEADLAMP, REMOVAL AND INSTALLATION .
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .