Troubleshooting RV Backup Lights Staying on When Towed Car is Connected

Question:

the back up lights on the 1998 Ford F450 C-Class motor home stay on when we plug in the towed vehicle. Never happened before, first time this season and trouble. Always worked fine last year. All the lights on both vehicles work fine when hooked up except the back up lights stay on on rv. Where do I start? Why would this happen?

asked by: Marilyn

Helpful Expert Reply:

The most likely cause for the RV backup lights to suddenly stay on when your towed vehicle is connected is corrosion in the RV connector. In a 7-way socket (please see photo) the 12V power contact at the 1:00 position and the backup light contact in the center can become bridged together. This can occur from corrosion on the inside of the connector or from trapped water or other foreign material that connects these two circuits.

You can try an aerosol electrical contact cleaner like Caig De-Oxit or you might prefer to just replace the 7-way with item # PK11893. It is also possible that the corrosion is in the wiring harness that feeds signals to the 7-way socket so you can inspect this part too while it is disconnected from the 7-Way and clean it or replace it with # 20147.

expert reply by: Adam R