F 450 4WD Super Duty V10-6.8L VIN D (2004)
Trailer Lamps: Initial Inspection and Diagnostic Overview
"Ford service information indicates the Trailer Tow Parking Lamp Relay is within the Central Junction Box (CJB). However, related system testing
and the CJB wiring diagrams do not indicate that the relay is serviceable seperate from the CJB".
INSPECTION AND VERIFICATION
1. Verify the customer concern by operating the trailer towing package.
2. Visually inspect for obvious signs of electrical damage.
Visual Inspection Chart
Electrical
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Central junction box (CJB) fuse:
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38 (20A)
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101 (30A)
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115 (20A)
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Circuitry
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Lamps
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Trailer tow turn/stop relays
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Trailer tow electric brake controller
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CJB
3. If the concern is not visually evident, verify the symptom and proceed to the Symptom Chart. See: Symptom Related Diagnostic Procedures
