My trailer light were working right but, now I stumped. The left side turn works but nothing else is working the right side stopped work completely. The fuses are good the two I found, the plug is well worn but theres no power to the back of the plug. There is a relay/relays somewhere but I cant fine it, have any clues? Because I cant find it, it's not were it should be.
trailer light hook up
- Thread starter Dogman
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silverF250
Full Access Member
The fuses you checked were the 7.5's under the hood? My brother and I spent 3 hours trying to figure out why the trailer lights worked when backing up and then all of a sudden they stopped. We hooked up both of our trucks and had the same results, we then hooked up our sister's tahoe and they worked. So we narrowed the problem down to our trucks and it was those fuses. Just recently plugging in to the 4 pin the lights stopped working, so I started using the 7 pin. It worked great for 4 months and now it isn't working. Now I get to replace the factory trailer hookups on the truck.
Big question are you getting power to the back of the truck?
Big question are you getting power to the back of the truck?
silverF250
Full Access Member
Well on our 01 and 00's we had two 7.5 amp fuses under the hood and that took care of it.
Have you crawled under the truck and checked the wires before the plugs?
Have you crawled under the truck and checked the wires before the plugs?
Not sure if this will help of not but on my '00 Excursion, after many hours of nothing making sense in the fuse department, it turned out the pins in the 7 pin socket had pulled back due to the angle of the harness entering it. Unplugged the small foot long harness attached to the socket from the main harness of the truck and pressed the pins back in until they snapped into place, haven't had an issue since.
Just another thing to check I guess.
Just another thing to check I guess.
Spire's right, and the same can happen on the plug end coming from the trailer. It should come apart with a small set screw, and the sleeve can be pulled back, exposing the wires. They can be corroded, loose, etc. You also know there's fuses under the fuses in the under-dash fuse box, I assume. You pull down the fuses you can see and there's another bank under those.
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silverF250
Full Access Member
Cool glad you got it fixed.
A Bad, or Weak Ground can be a purdy common gremlin with truck to trailor connections too. Located the ground wire in the OEM trailor towing pigtail and spliced/soldered a 10 gauge wire into it.. Grounded it off to the plug in bracket nut & bolt.
Also replaced the lighting Fuses with mini 12v Breakers.
FWIW
Also replaced the lighting Fuses with mini 12v Breakers.
FWIW
