Section 18-01: Wiring and Circuit Protection | 1996 F-150, F-250, F-350, F-Super Duty Chassis Cab, Motorhome Chassis, and Bronco Workshop Manual |
Check the trailer feed wiring (13A576) and the added trailer connector for obvious signs of damage.
Check fuses for damage.
If the concern remains after these checks proceed to the following symptom chart.