Blowing Fuses! New Trailer Lights Harness the cause but WHY - Any help?

[1986Blazer]

I just installed a trailer light harness made by Hoppy. It is a harness made for 85-91 Blazer and it connects to the brake light terminal harness. It has blown the fuses for the brake lights, turn signals and the dash lights. I tried fuses 5 amps more than the fuse block called for but they also blew. I have the harness grounded to the frame, which should be a good ground......has anyone else encountered this problem?? If so, any recommendations for a fix!

 

[Skigirl]

Maybe you wiggled something in the original wiring. You've got a short, I'd check to see if the original power wires are touching each other or ground at some break in the insulation.

Or you have it wired up wrong... power to ground somehow.

 

[Tybee]

I had this problem when I rented a trailer from uhaul, it ended up being the ground. They ran a wire from the trailer frame and wraped the other end around metal on the hitch. pulled it off quit blowing fuses and it worked fine.

 

[sapper]

does it do all the time or just when trailoring? mine would do that when i had the truck hooked up because two wires got exposed and crossed as soon as i hooked up pop went my fuses.

 

[four_by_ken]

I had my two wires crossed in my plug, and every tie I hit the breaks, the fuse would blow. That would be where I would check first. Crossed wires somewhere.

Ken H.

 

[txbartman]

Make sure it isn't the wiring in your trailer that is causing it, too. I had this problem with my boat trailer. Turns out the wiring was bad on the trailer side. The short was in the trailer, not the rig. But the rig suffered the brunt of the problems.

 

[1986Blazer]

This does it without the trailer hooked up.......I am going to check some things today and see if I can figure it out.....any more ideas??

 

[four_by_ken]

If nothing else has been changed, then I would double check the plug again. If wires are crossed in the truck half of the plug, the trailer would not have to be attached in order fro something to go wrong.

Ken H.

 

[lugnut]

Unplug the new harnes and see if the problem goes away.

 

[CV202]

Make sure you have a heavy duty flasher in you rig too....The stock cheapies seem to go quick with more than a couple extra lights after a couple of runs.

 

[HarryH3]

First thing to do is PUT THE RIGHT FUSES BACK! Using an oversize fuse is a great way to set your truck on fire. A dead short will usually blow the fuse anyway (if you're lucky), but a slight overload can overheat the wiring. They picked the fuse sizes for each circuit for a reason. /forums/images/icons/shocked.gif

 

[1986Blazer]

Yea, yea, yea....I used larger fuses just so I could get home from the marina with brake lights. I have the correct size fuses in again. I have traced the wires and found that one of the wires for the drivers side light harness was split. I am going to replace it this weekend. I removed the trailer light connector and everything is fine. I'll try again once i fix the wire.