Troubleshooting Trailer Wiring Harness for Class C Motorhome on 1998 Ford E350 Van Cutaway Chassis

Updated 01/06/2015 | Published 01/05/2015

Question:

I do not know if I have a harness presently on my motorhome. There is a 4 pin connector installed to go to the trailer harness but dont work. I cant get any electrical current to the 4 pin connector ?

asked by: Gordon M

Expert Reply:

I would first spend a few minutes trying to trace the wires feeding that 4-pole trailer connector you found. If the white ground wire had come loose from its connection with the RV frame or chassis, it would explain why you're not getting any voltage at the connector.

If that fails, you'll need to simply hardwire in a new trailer connector like part # 18002. The green wire would tap into the right turn signal circuit, the yellow wire into the right turn circuit signal and the brown wire would connect to the running light circuit. This assumes that your Class C motorhome uses a combined taillight system, with the same bulb being used for the brake lamps and the turn signals. A combined system will NOT have amber lenses on the turn signals.

If your Motorhome has yellow turn signal lenses, you have a separately wired taillight system that uses separate bulbs for the brake lamps and turn signals. If this is the case, use part # 119178, which would wire as described above, with the red wire being tapped into a brake lamp circuit.

The # C55344 wiring harness you referred to is a fit for the 1998 Ford Van, but since your vehicle is a motorhome, it won't use the same taillights as the van would.

I've linked you to our trailer connector troubleshooting article.

expert reply by: Mike L