Inspection and Verification

INSPECTION AND VERIFICATION

1. Verify the customer concern.
2. Visually inspect for obvious signs of electrical damage.

VISUAL INSPECTION CHART

Electrical
- Central junction box (CJB) fuse(s):
- 10 (20A) (trailer tow parking and reversing lamps)
- 13 (10A) (trailer tow battery charge relay coil side)
- 36 (10A) (trailer tow RH stop/turn)
- 42 (10A) (trailer tow LH stop/turn)
- 105 (30A) (trailer tow electric brakes)
- 106 (30A) (trailer tow battery charge relay switch side)

- Bulb(s)
- Relay(s)
- Wiring, terminals or connectors
- Trailer brake control module (TBCM)
- Trailer tow connector
- Trailer

NOTE: When diagnosing the trailer tow lamps, begin by verifying that the vehicle exterior lighting systems are all operating correctly with the trailer disconnected.

3. If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to the next step.
4. If the concern is not visually evident, verify the symptom. GO to Symptom Chart. Symptom Related Diagnostic Procedures