Troubleshooting Damaged Trailer Wiring That is Causing Vehicle Fuses to Blow in Honda Odyssey

Question:

I had some stripped wires in my trailer which probably caused a short I replaced one 7.5A fuse in the passenger side box and restored power to the tail lights however, the right and left turn signals still dont work. Can you tell me where the fuses for the trailer turn signals are. Thanks

asked by: Robert L

Expert Reply:

Damaged trailer wiring, such as worn insulation that can cause a short, should be repaired before you replace your vehicles fuses or chances are that you will be doing that regularly. In some cases a short on a trailer can damage a tail light converter, such as the Curt T-Connector Vehicle Wiring Harness # C56161 that you referenced.

Check your trailer wiring all the way from the connector to the light fixtures themselves. Inspect the wires for cracked or worn insulation, especially in spots where the wires have to make bends and where they may come into contact with sharp edges on the trailer frame. Repair or replace any suspect wires and ensure the ground wire on the trailer is secured to a clean bare metal surface.
A bad ground can sometimes lead to some light functions not working.

I suggest you test your 4-pole wiring harness with a tester like # PTW2993 to check that it is still functioning. Apply the tester to the yellow wire on the left INPUT side of the harness while a helper activates the left turn signal; repeat this on the green wire with the right turn signal activated.
You should detect an on-and-off signal on these wires; if not then check the connections to the vehicle. If you have turn signals going in to the box then test the 4-pole connector; if signals are going in to the box but not coming out then the unit needs to be replaced.

Once you have corrected any trailer wiring problems and confirmed the harness still operates then you can check/replace any fuses in the engine compartment or passenger-side fuse boxes that are labeled "trailer" or "tow".

I have linked for you a video on how to use the tester and an article on how to troubleshoot your trailer and vehicle wiring.