Troubleshooting Curt T-Connector Blowing Fuse on 2010 Toyota Rav4

Updated 07/18/2020 | Published 12/01/2014

Question:

I purchased and installed a trailer wiring harness on my 2010 Toyota Rav that I purchased. I followed the video for the installation. Originally the fuse at the battery terminal would blow after a short time and now blows as soon as I it in the fuse holder. HELP! Thanks

asked by: Ron T

Expert Reply:

Is this occurring with the trailer plugged in or was it unplugged?

If it's happening with the trailer plugged in, the likely cause is a short in the trailer wiring. You'll want to examine the running light circuit, which is usually a brown wire, the right turn/brake which is usually a green wire and the left turn/brake which is usually a yellow wire. Begin at the trailer connector, and trace your way back to the lamps, looking for pinched wires, loose connections, and nicked, worn or cracked wire insulation that would allow the copper wire to come into contact with the trailer frame and create a short circuit that would blow the fuse you mentioned. Once the short is found, repair it and you should be good to go.

If it's not happening with a trailer plugged in, carefully examine the plugs where the converter taps into the vehicle wiring. Look for bent pins, and once again check for nicked, cracked or worn insulation. I'll link you to an FAQ article that has further information about troubleshooting your trailer wiring. I'll link you to some videos that will also illustrate how to locate and repair a wiring short.

expert reply by: Mike L

Gerard E.

7/7/2020

I have a 2012 Toyota corolla and a curt wiring harness when i plug into my trailer signal lights work perfect brake lights work perfect but as soon as I turn in the parking lights it blows the fuse in the car. can you please give me some advice thank you

Chris R.

7/12/2020

This could be a weak ground on the harness. Check the Curt harness on your Corolla and make sure the white wire is still securely grounded to a clean portion of bare metal. Do the same thing with the main harness ground on the trailer. Let me know what you find and we can keep troubleshooting if needed.

Gerard E.

7/13/2020

@ChrisR Thank you for your help I ran a ground wire from the white wire of the curt harness to the chassis of the car worked perfect