Trailer wiring not working
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Tuned
Joined: Jun 2013
Posts: 344
Likes: 5
From: North Shore MA
Trailer wiring not working
My trailer wiring is not working, at least from what I can tell. Embarrassingly, I know this because the little brake light I have in my trailer hitch no longer lights up. I've tried different bulbs and a different unit, so it's definitely the wiring. I do not have access to a trailer right now, so unfortunately that's all I have to go on. It's plugged into the 4 pin jack. Is this something I should be going to the dealer for, or more like a blown/loose fuse or something?
Cargo Master
Joined: Nov 2005
Posts: 2,051
Likes: 10
From: TEXAS
Been there, done that, fixed it with the replacement of the #100 fuse located in the power distribution box located under the hood between the front driver side fender well and the firewall. 25 amp square fuse, that is not as easy to find a replacement for as one would think possible. However FWIW, NAPA does stock them behind the counter.
Logistics Pro
Joined: Jul 2002
Posts: 4,821
Likes: 19
From: South Dakota
My trailer wiring is not working, at least from what I can tell. Embarrassingly, I know this because the little brake light I have in my trailer hitch no longer lights up. I've tried different bulbs and a different unit, so it's definitely the wiring. I do not have access to a trailer right now, so unfortunately that's all I have to go on. It's plugged into the 4 pin jack. Is this something I should be going to the dealer for, or more like a blown/loose fuse or something?
The male terminal on the truck is ground. The others are left turn/brake right turn/brake and running lights.
Flip on your hazards and running lights. If you have 2 that blink 12 volts an one that is steady 12 volts you are good to go.
Thread Starter
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Tuned
Joined: Jun 2013
Posts: 344
Likes: 5
From: North Shore MA
Been there, done that, fixed it with the replacement of the #100 fuse located in the power distribution box located under the hood between the front driver side fender well and the firewall. 25 amp square fuse, that is not as easy to find a replacement for as one would think possible. However FWIW, NAPA does stock them behind the counter.
Posting Guru
Joined: Dec 2008
Posts: 1,226
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From: Rusty, Maine
You're probably talking about fuse #90, trailer accessory.
Lead Driver
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Hotshot
Joined: Jul 2005
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From: Middle Tn.
You'd better check that the wires are rated for 40 amps or you could have a vehicle fire on your hands.
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Thread Starter
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Tuned
Joined: Jun 2013
Posts: 344
Likes: 5
From: North Shore MA
Been there, done that, fixed it with the replacement of the #100 fuse located in the power distribution box located under the hood between the front driver side fender well and the firewall. 25 amp square fuse, that is not as easy to find a replacement for as one would think possible. However FWIW, NAPA does stock them behind the counter.
Cargo Master
Joined: Nov 2005
Posts: 2,051
Likes: 10
From: TEXAS
Manual says to disconnect the battery? Nope, I missed that page I guess.
It pulled straight up and inserts the same, I guess I can see where disconnection the battery would make sense and protect from crossing the fuse block. I just used old fashion care and had no problems.
Thread Starter
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Tuned
Joined: Jun 2013
Posts: 344
Likes: 5
From: North Shore MA
Manual says to disconnect the battery? Nope, I missed that page I guess. It pulled straight up and inserts the same, I guess I can see where disconnection the battery would make sense and protect from crossing the fuse block. I just used old fashion care and had no problems.
Cargo Master
Joined: Nov 2005
Posts: 2,051
Likes: 10
From: TEXAS
OK, just to back track.
The truck lights work, it's only the trailer plug that does not......correct?
And this is only the 4 pin plug or is it both the 4 pin and 7 pin trailer plugs that don't work?
Check them both and see if it is 1 or the other or both.
Up between the rear bumper and the spare tire is a male/female plug where the trailer harness plugs in to the main wire harness. Make sure that this is plugged in tight and that there hasn't been dirt or such that is blocking the connection. This is also a good point to use a simple tester to check power to the end of the harness at this point. I could help you to isolate the problem as to the problem being in the harness itself.
If it would help I could take a photo of the pages out of the owners manual and email them to you. But, you by now may have already received your ordered owners manual or located one on line.
The truck lights work, it's only the trailer plug that does not......correct?
And this is only the 4 pin plug or is it both the 4 pin and 7 pin trailer plugs that don't work?
Check them both and see if it is 1 or the other or both.
Up between the rear bumper and the spare tire is a male/female plug where the trailer harness plugs in to the main wire harness. Make sure that this is plugged in tight and that there hasn't been dirt or such that is blocking the connection. This is also a good point to use a simple tester to check power to the end of the harness at this point. I could help you to isolate the problem as to the problem being in the harness itself.
If it would help I could take a photo of the pages out of the owners manual and email them to you. But, you by now may have already received your ordered owners manual or located one on line.
Thread Starter
|
Tuned
Joined: Jun 2013
Posts: 344
Likes: 5
From: North Shore MA
OK, just to back track.
The truck lights work, it's only the trailer plug that does not......correct?
And this is only the 4 pin plug or is it both the 4 pin and 7 pin trailer plugs that don't work?
Check them both and see if it is 1 or the other or both.
Up between the rear bumper and the spare tire is a male/female plug where the trailer harness plugs in to the main wire harness. Make sure that this is plugged in tight and that there hasn't been dirt or such that is blocking the connection. This is also a good point to use a simple tester to check power to the end of the harness at this point. I could help you to isolate the problem as to the problem being in the harness itself.
If it would help I could take a photo of the pages out of the owners manual and email them to you. But, you by now may have already received your ordered owners manual or located one on line.
The truck lights work, it's only the trailer plug that does not......correct?
And this is only the 4 pin plug or is it both the 4 pin and 7 pin trailer plugs that don't work?
Check them both and see if it is 1 or the other or both.
Up between the rear bumper and the spare tire is a male/female plug where the trailer harness plugs in to the main wire harness. Make sure that this is plugged in tight and that there hasn't been dirt or such that is blocking the connection. This is also a good point to use a simple tester to check power to the end of the harness at this point. I could help you to isolate the problem as to the problem being in the harness itself.
If it would help I could take a photo of the pages out of the owners manual and email them to you. But, you by now may have already received your ordered owners manual or located one on line.
Cargo Master
Joined: Nov 2005
Posts: 2,051
Likes: 10
From: TEXAS
First thing I would do is to check the 7 pin trailer plug. If all of the lights work on the 7 pin then you will know that the problem is going to be at the junction where the 4 pin and the 7 pin meet and separate.
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