Initial Inspection and Diagnostic Overview

INSPECTION AND VERIFICATION

1. Verify the customer concern.
2. Verify the exterior lighting system of the vehicle is operating correctly. If not, refer to the appropriate pinpoint test.
3. Visually inspect for obvious signs of electrical damage.

VISUAL INSPECTION CHART

Electrical
- Battery junction box (BJB) fuse(s)
- 8 (40A) (trailer tow battery charge relay - switched)
- 10 (30A) (trailer tow electric brake controller)
- 24 (20A) (trailer tow reversing and parking lamps)
- 26 (20A) (trailer tow stop/turn lamp relays)
- Central junction box (CJB) fuse 15 (5A) (trailer tow battery charge relay coil)
- Relay(s)
- Trailer tow electric brake controller
- Trailer
- Circuitry
- Bulb(s)

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