Tail Light Fuse Blows On 2000 Toyota Tacoma When Trailer Is Connected To The Trailer Hitch


When I plug my trailer lights into the receptacle on my truck, and then turn my head lights/tail lights on, the fuse blows. This only happens when the trailer is actually connected to the hitch. If the trailer is *not connected to the hitch*, the fuse will not blow. HOWEVER, if the tail lights are activated, there is no change in the lights when I apply brakes or turn on the turn signals testing in the garage. I installed the t-one wiring harness for my specific vehicle. Is there something else I need to make all of the lights function properly? Thanks for your help.


Expert Reply:

Since it is blowing the fuses only when the trailer is connected to the hitch it is probably a short on the trailer wiring.

You will want to start by testing the installation of the T-One Vehicle Wiring Harness, # 118379.

Without the trailer hooked up you will need to use a circuit tester like part # 40376, and test each wire going into the black converter box on the T-One Vehicle Wiring Harness, # 118379, as its function is activated. With somebody to turn on the turn signals and step on the brakes, test each wire to see that it is working properly. Also, make sure the ground is attached to a good grounding point. Next, would be to test the wiring coming out of the converter to the trailer connector on the vehicle.

If the wires going in to the converter test good and if the wires coming out are not working then it is a problem with the converter.

If all the wiring is working properly on the vehicle and the ground is good you will want to check the trailer wiring. Check each circuit on the trailer and make sure that each wire is run to the correct circuit on each taillight. Check all the wiring on the trailer to make sure there is no pinched or frayed wire.

You will want to take time when checking the wiring on the trailer because that is where it sounds like you might be having a problem.

Also, make sure to check that the grounds for the trailer lights and light brackets are making contact to clean paint and corrosion-free metal on the trailer frame.

I am sending a link to a page on how to troubleshoot your trailer wiring. It will describe in detail how to test your trailer wiring.

expert reply by:
Jeff D

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