Turning On Headlights Stops Brake Lights From Working

Question:

Hi, Ive seen this type of question before but Im at a loss. Ive replaced my trucks 7 pin connector, the campers 7 pin harness, and have two new rear lights. Everything works as it should until I turn on the headlights then I have no turn signals or brake lights on the camper. As a matter of fact, it appears that the brake light and filament for the turn signals are on at the same time on both sides with headlights on very bright. I even attached another ground wire to the frame and the ground connection on the camper, still the same. I used a test light on the truck side to verify voltage there. Only thing I removed was the battery on the camper as I wont be using it and will be using shore power at sites. Helpppppp please

asked by: Rich

Expert Reply:

The issue you are having, with the headlights causing other issues is a pretty common one. It is so common that in our help article on troubleshooting trailer wiring it is one of the problems we have highlighted (I have linked this article for you which I very strongly recommend reading).

The issue is almost certainly a ground problem as it can cause all sorts of funky issues like what you are experiencing. You'll also need to make sure your grounds are attached to bare metal surfaces and free of any paint, dirt or corrosion or this is very likely to continue. Once you have improved your ground I'm willing to bet you'll see the issue disappear.

That said, you will want to check your wires as well; go over them and look for any type of crimped, broken or otherwise damaged wires and replace as needed.

expert reply by: Kyle S