Navigator 4WD V8-5.4L (2010)
Trailer Lamps: Initial Inspection and Diagnostic Overview
Special Tool(s) Used With Diagnostics
Trailer Lamps
Principles of Operation
Trailer Lamps
Principles of Operation
NOTE: The Smart Junction Box (SJB) is also known as the Generic Electronic Module (GEM).
The trailer lamps and battery charge are supplied power by relays that are energized to correspond with the exterior lighting functions of the vehicle. If
equipped, the vehicle also supplies circuitry to support the installation of an aftermarket Trailer Brake Control (TBC) module (installed by the customer).
The vehicle circuitry only supplies voltage, ground, stoplamp switch input and a controlling circuit to the trailer tow connector. The trailer electric brakes
themselves are controlled by the aftermarket TBC module and not the vehicle itself.
Vehicles equipped with the heavy duty trailer tow package are also equipped with a trailer sway control feature. For diagnostics and other information
regarding this feature, refer to Antilock Brakes / Traction Control Systems.
Inspection and Verification
Trailer Lamps
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
