Trailer light issues
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Mountain Pass
Joined: Nov 2016
Posts: 195
Likes: 2
From: AK
Trailer light issues
I've had issues with the trucks trailer hookup electrical for a long time now. I've re-done the wiring harness in the back and replaced the trailer plug, done it properly with wiring diagrams in hand and I've gotten everything to work on the trailer except for the right turn signal and right brake light. Running lights work both sides, left turn signal and brake light works and trailer brakes work. I got a trailer plug that has an led indicator to tell you if it had power on each pin and everything lights up except for the lights that I mentioned don't work. So it should be on the truck side... I've traced the wiring harness all the way to the fuse box and it all appears fine. What am I missing? What should I do??
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Mountain Pass
Joined: Nov 2016
Posts: 195
Likes: 2
From: AK
I've messed with the fuses and they look fine, though I pulled out the manual today and looks like the previous owner had installed higher amperage fuses than recommended. One was supposed to be a 7.5 and there was a 15 in its place, others were 5 amps too high, one was too low. You think I have wire damage somewhere on that right turn wire? That's one that had too high an amperage fuse installed.
More Turbo
Joined: Jun 2017
Posts: 731
Likes: 15
From: Arizona
I just had issues with my trailer wiring. The brake controller would read connected and then not connected throughout my last towing endeavor. Turned out to be one of those little clamps that are meant to splice a wire into a feed line.
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Mountain Pass
Joined: Nov 2016
Posts: 195
Likes: 2
From: AK
I had to replace the harness by the hitch because the old one had been patched and re-crimped many times by the previous owner. Each wire had at least 1 butt connector on it, some had 2. But I traced the rest of the wire loom up to the fuse box and they look fine...
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Mountain Pass
Joined: Nov 2016
Posts: 195
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From: AK
This is what I replaced because the old one was in terrible shape. I was having issues before doing this, and the new one improved the situation but now that I'm digging more I've got bigger issues than I thought I did.
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Mountain Pass
Joined: Nov 2016
Posts: 195
Likes: 2
From: AK
My main question now is how do I find the problem? This harness is good, I've got continuity from one end to the other, but from there to the fuse box, there must be issues. I have no idea where to look! I took the fuse box out and looked at the underside and couldn't see any obvious problem. But I've still got no right side blinker or brake light. All running lights work but as I said that fuse blew while driving yesterday. So I've got issues. Where though?????
More Turbo
Joined: Jun 2017
Posts: 731
Likes: 15
From: Arizona
It's got to be in the connection to the truck harness. I would trace the right brake light line from the connector (the part you replaced) to the truck harness. My guess is there is a break in the line or a bad connection. I am assuming that the right blinker/brake light works on the truck so where the feed line to the trailer connector is would be a good place to start.
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