Troubleshooting a Wiring Issue on Older Harbor Freight Trailer Being Towed by a 2003 Honda Odyssey

Question:

vehicle: Honda 2003 odyssey harbor freight trailer I have connected the etrailer harness to the trailers 4 pole connector. When I turn on the left tail signal nothing happens, when I turn on the right signal, both tail lights signal. When I turn on the running lights nothing works: no tail light, brake or turn signal. The trailer fairly old and I repaired any nicks or brakes in the wiring I can find. Any help with this problem would be greatly appreciated.

asked by: Will

Expert Reply:

As you have probably already figured out, something is not wired correctly on your trailer wiring. Most likely it is the trailer since you said the trailer is older. However, I would still recommend you test the wiring of your 2003 Honda Odyssey just to be sure.

You are going to want to test the 7-way at the rear of your vehicle by function using a circuit tester. You will want to have a buddy in the driver seat of your vehicle and then using a circuit tester like our # PTW2993 you would want to test the circuits of the 7-way for voltage when the correct tail light function is being applied. Check out the picture I attached that shows all of the different functions of a 7-way so you know which circuit does what.

If that checks out you will need to plug in the Hopkins Wiring Adapter # 37385 and basically repeat the same process. Check out the video I attached that shows how this is done. If everything checks out at this point then you know the problem is on the trailer side of the setup.

At this point I would first check the trailer connector looking for corrosion, exposed wire or anything else that might cause a short and fix as necessary.

Next, I would check to make sure that all of the grounds of your trailer are making a good, clean connection to a metal portion of your trailer.

I attached an FAQ on trailer wiring for you to check out also.