Ranger 2WD V6-3.0L (2008)
Trailer Lamps: Initial Inspection and Diagnostic Overview
Principles of Operation
PRINCIPLES OF OPERATION
NOTE: The smart junction box (SJB) is also known as the generic electronic module (GEM).
Circuitry is supplied to the trailer tow connector to support trailer parking lamps and stop/turn lamp functionality. When the vehicle parking lamps are
on, the smart junction box (SJB) supplies voltage to the trailer tow connector for the trailer parking lamps. When the vehicle stop/turn lamps are
operating, voltage is supplied to the trailer tow connector for the trailer stop/turn lamps.
Inspection and Verification
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
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Battery junction box (BJB) fuse(s):
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38 (7.5A) (trailer tow RH stoplamp)
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42 (7.5A) (trailer tow LH stoplamp)
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Smart junction box (SJB) fuse 2 (10A) (trailer tow parking lamps)
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Wiring, terminals or connectors
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Bulb(s)
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SJB
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. See: Symptom Related Diagnostic Procedures
