Diagnostic Test

Turn the ignition on.

With the scan tool, clear all DTC's

Turn on the Left Turn Signal.

With the scan tool, read DTC's.

Does the scan tool display active: B166C-LEFT TRAILER TOW LAMP CONTROL CIRCUIT HIGH? 

Yes 

1. Go to  2).

No 

1. The condition that caused this symptom is currently not present. Check for an intermittent condition by inspecting the related wiring harness for chafed, pierced, pinched, and partially broken wires. Also, inspect the related connectors for broken, bent, pushed out, spread, corroded, or contaminated terminals. Repair as necessary.
2. Perform BODY VERIFICATION TEST - VER 1 .

Turn the ignition off.

Disconnect the TIPM C6 harness connector.

Disconnect the Left Trailer Tow Lamp harness connectors.

Measure the resistance of the (L673) Left Trailer Tow Lamp Control circuit between the Left Trailer Tow Lamp harness connectors and the TIPM C6 harness connector.

Does the ohm meter read open circuit? 

Yes 

1. Repair the (L673) Left Trailer Tow Lamp Control circuit for an open.
2. Perform BODY VERIFICATION TEST - VER 1 .

No 

1. Go to  3).

Turn the ignition on.

Measure the voltage on the (L673) Left Trailer Tow Lamp Control circuit.

Is there any voltage present? 

Yes 

1. Repair the (L673) Left Trailer Tow Lamp Control circuit for a short to voltage.
2. Perform BODY VERIFICATION TEST - VER 1 .

No 

1. Replace the Totally Integrated Power Module (TIPM) in accordance with the Service Information.
2. Perform BODY VERIFICATION TEST - VER 1 .