bing tracking image
Q & A Icon

Troubleshooting Trailer Wiring and Non-Functioning Running Lights with Honda Odyssey 4-Pole Harness


We purchased wiring harness from you. When we hook it up to camping trailer, we can get either the running lights to work OR brake and blinkers but not both. Suggestions?


Expert Reply:

I could not find purchase history based on your email address so I do not know which particular trailer wiring harness you have but I can still help you troubleshooting it.

Most often when one lighting function fails to operate while other do operate correctly the cause is related to a grounding issue. What can happen is that if the ground is weak it will allow enough current for some light functions to operate but not pass enough current to allow all to work at once. This usually does affect the running lights more than the other lights since these light remain on continuously, as opposed to being on for a short period of time as when braking or signaling.

This issue can affect either the vehicle harness, the trailer harness or both. The fix can be as simple as merely sanding off the grounding point or moving the ground ring terminal to a new spot on the vehicle or trailer frame. The ground must make tight metal-on-metal contact to a clean bare spot on the frame, one that is free of rust, grease, paint, primer or undercoat. Bare metal-to-metal ground contact for both the vehicle and trailer wiring usually corrects this issue.

Once you have made these clean ground connections you can help protect them from future corrosion with an application of protective dielectric grease # 11755. The dielectric grease will help block entry of water and contaminants into the ground connection points.

expert reply by:

Product Page this Question was Asked From

Q & A Icon

Similar Expert Q&A Pages

See More Q&A Expert Answers >>