Troubleshooting Malfunctioning Trailer Wiring Harness on 2013 Lexus RX350

Updated 02/02/2016 | Published 02/01/2016

Question:

Hello, I purchased and installed the trailer hitch and the wiring harness from you on my 2013 Lexus. The lights are not working. The local trailer shop did extensive testing, no luck. I found the factory installed light adapter and simply plugged in the wiring adapter. Is there anything that you can recommend to make the lights work? I was wondering if Lexus provides the factory adapter and only connects it and it only works if the tow package was purchased. Thanks!

asked by: John L

Expert Reply:

I'm assuming you have a 2013 Lexus RX350. Did the # 56083 wiring harness ever work, or did it work for awhile and then stop?

From my research, the connector should work once plugged into the factory towing connector under the vehicle, unless your vehicle isn't equipped with the tow package. If the tow package wasn't purchased, you'll need to add the fuses or relays to activate the tow package. I'd recommend you check your owner's manual or with Lexus, as I was unable to access an online copy of the owner's manual.

If the plug once worked but has now stopped, you've likely blown one of the tow package fuses. The owner's manual should be able to tell you which fuses to check. Before replacing the fuses, be sure to carefully check the trailer wiring for any short circuits. Trace each lighting circuit, looking for pinched wires or any cracked or worn wire insulation. If you don't locate and repair the short, you'll continue blowing fuses.

I'll link you to our trailer wiring harness troubleshooting FAQ article. I hope you'll find it helpful.

expert reply by: Mike L