Brake Light Fuse Keeps Blowing After Installing a Trailer Wiring Harness
Question:
Ok I have no brake lights I checked the fuses and found it was blown so I replaced it and every time you apply the brake it blows the fuse strait away what is this and how do I fix it please and what would make this happen all of a sudden as I havent been towing a trailer
asked by: Sonia
Expert Reply:
What you are describing is a classic short circuit. Two wires touching or a wiring touching bare metal, a wire attached to the wrong location, and even corrosion can cause over draw on the circuit and blow that fuse.
If it were to happen only when connected to a trailer then the short would be on the trailer side. You would have to check the trailer connectors to make sure they are clean and free of corrosion, check the wiring for any pinched, frayed, or otherwise damaged wires, and make sure that the wiring is going to the correct lights.
I have included a couple of links that should also help.
Erik P.
6/20/2020
I have a 2013 F-150 that keeps blowing the trailer signal/brake fuse under the hood when I have my "brand new" trailer plugged in and apply the brake. It's the round 7 pin plug. Signals and running lights work fine until you touch the petal and it blows the fuse. Then no signal or brake lights on trailer. I even hooked up to a different brand new trailer and same thing happened and I've crawled all under my trailer checking for bare wires, etc... Replaced the fuse and checked plug on truck with test light and everything works as it shld. I'm stumped and wld appreciate any advice/help. Thanks!
Chris R.
6/24/2020
Product Page this Question was Asked From
4-Way Flat Trailer Connector w/ 60" Harness and Wire Taps
- Trailer Wiring
- Trailer Connectors
- Vehicle End Connector
- 0 - 5 Feet Long
- Plug and Lead
- 4 Flat
- Tekonsha
more information >
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Doug
8/4/2020
I'm having the same problem. A trailer I've used before without problem, when I attach it to a new (2nd hand) vehicle and hot the brakes a fuse blows and the brake lights no longer work on the vehicle - nor obviously on the trailer. Multimeter shows nothing amiss when the trailer is not attached. Thanks!