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
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - Perform the TESTING FOR INTERMITTENT CONDITIONS procedure. Refer to TESTING FOR AN INTERMITTENT CONDITION .
CHECK THE TRAILER TOW MODULE (TTM) AND TRAILER LEFT TURN LAMP CONNECTIONS
1. Check for loose, damaged or corroded connections at the Trailer Tow Module (TTM) and Trailer Left Turn Lamp.
  Are there any loose or damaged connections?
  
  Yes
  - Repair the wiring connections as necessary.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - Go to 3.
CHECK THE OPERATION OF THE TRAILER LEFT TURN LAMP
1. Disconnect the Trailer Left Turn Lamp.
2. Turn the ignition on.
3. Turn the Left Turn Lamps on.
4. Connect a 12 volt test light between ground and the Trailer Left Turn Lamp.
  Does the test light illuminate On and Off in sequence with the Left Turn Lamps?
  
  Yes
  - Replace the Trailer Left Turn Lamp in accordance with the Service Information.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST STANDARD PROCEDURE .
  No
  - Repair the open on the Trailer Left Turn Lamp circuit.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST STANDARD PROCEDURE .