Troubleshooting a T-One Tow-Ready Hitch Wiring Adapter # 118409 Not working Properly

Updated 07/23/2010 | Published 07/22/2010

Question:

I have wired this harness as shown in the videos, but when I connect it to a trailer and try to use the left turn signal, I get the turn signal to blink, but the clock, dash and headlights also blink. Any idea what could cause this?

asked by: Eric Y

Expert Reply:

If the vehicle lighting is working properly with the trailer wiring harness # 118409, installed and no trailer connected, the problem could be that you have the wires from the harness connected on the wrong sides of the vehicle or you have a problem with the wiring on the trailer.

I suspect that there is a bad ground connection on the trailer and that when the trailer is connected the problems that arise will go away when the ground fault is corrected. Check the connection of the white ground wire at the trailer coupler, and where the trailer lights are grounded to the trailer frame. If the lights are grounded through their mounting studs make sure they are making good contact to clean paint and corrosion free metal. Make sure there is not a plastic license plate bracket causing a bad ground and, the light brackets could be bolted to the trailer frame and not making a good ground connection.

If all ground connections are verified you will need to look for a broken pinched or frayed wire, that could be the cause of the problem.

You could also have the incorrect wiring harness for your vehicle. Let me know the year, make and model of your vehicle and, I will be glad to make sure you have the correct harness for your specific vehicle.

expert reply by: Robert G