Front Clearance/Side Marker Lights Dont Work But All Other Trailer Lights Do Work

Question:

Top two front clearnace and front two side running lights dont work the rest of the running lights do and so do the turn signals and tail lights. I have replaced the bulbs, used CRC cleaner to clean the metal terminals, connected a new light fixture checked under the front of the camper where all the wires connect in and found the brown wire had some plastic coating that was gone and put electricial tape over it, all the rest of the wires look good and so do the wire nut connections. I did notice that the bolt which Im assumming is the ground is rusted but wouldnt that then make none of the lights work and not just some of them. If it was a fuse on the truck that would also effect all the lights and not just some of them. I checked inside the camper for another panel box and did not find one so Im assuming that the one under the camper is where i should be looking. Can you tell me how else to check to find the culprit that is causing this?

asked by: Ruth

Expert Reply:

The rusted ground location could create a weak ground so that some of the lights (usually the ones closest) could still work but others may not so it is worth cleaning away any corrosion. On the wire you mentioned that was exposed that you then taped corrosion could have gotten in and/or there could be other unseen damage.

If you were to disconnect some of the lights attached to the running light circuit and that causes those front clearance/running lights to start working then the issue is likely that there is excessive draw on the running light circuit and switching to LED lights would solve that problem. I have linked all of the LED lights we carry.

Another thing to consider is that some lights will ground through their mounting hardware. Any corrosion at the lights would make a bad ground and that could be the cause.

expert reply by: Michael H