Troubleshooting Blown Fuses After Installing Wiring Harness in 2013 Honda Pilot EX-L

Question:

I installed part 118265 on my 2013 Honda Pilot EX-L without problem. Unfortunately one or both of the 7.5 amp fuses in the auxillary fuse box keep blowing when I hook up the trailer. This is affecting the turn signals and brake lights. The running lights work fine. Any suggestions? Thanks.

asked by: Scott

Helpful Expert Reply:

It sounds like your wiring harness is either seeing an excessive power draw from the trailer lights or there is a short in the trailer's wiring causing the fuses to blow. I suggest you disconnect the trailer from the vehicle. This will let you test the 7-way with a circuit tester and test the trailer lights directly by applying a 12V power source to the trailer plug's contacts. Please note that this harness can handle up to 4.2-amps per stop/turn circuit. If you can determine the current draw from your lights, you can compare to the harness' output.

To test the Pilot's 7-way you'll need to disconnect the trailer and have a helper activate the lighting functions one by one while you apply a tester like # PTW2993 to the 7-way. The linked video shows how to use a tester. The linked photo shows you the usual functions assigned to the pins on a 7-way. If the 7-way has the correct signals present, then you can move on to testing the trailer. If not make sure all fuses are okay and that the harness connectors and relays are fully seated in their mating plugs.

First inspect the trailer plug for any signs of even slight greenish or whitish discoloration. This can indicate corrosion that could cause a short and blow your fuses. Clean the plug's contacts as needed.

The trailer can be tested by applying 12V power directly to the trailer plug's contacts. You can use the Pilot's battery or a spare 12V if you have one around. The battery ground terminal connects to the ground on the trailer plug and the positive terminal connects one at a time to each of the affected lighting circuits' pins. You'll want to check the condition of the trailer wiring from the plug all the way to the affected lights. Look for signs of cracked or worn insulation, especially around spots where the wire has to make sharp bends and where it may rub on the trailer frame. Repair or replace any damaged wire as needed.

expert reply by: Adam R