Troubleshooting Running Lights Not Working On Trailer When Hooked To 2012 Chevrolet Silverado

Question:

Hi, I have a 2012 Chevy Silverado. I recently used it to tow a friends trailer. Upon initial connection to his trailer, my running lights worked. After towing it to another location I noticed my running lights on the trailer did not work. I also connected to my own trailer and now I have no running lights to that trailer either. I have checked all the fuses that I can find that might be related to the trailer lights, and they all seem fine. All the lights on my truck seem to work just fine. However, when I use a 4 way plug tester, the tail light/running light wont light. All my other lights work. Any suggestions!

asked by: Jeff

Helpful Expert Reply:

Since you said the problem exists for two different trailers, the problem will be found in the truck wiring. You said you checked all of the fuses and they are okay and then you said you used a circuit tester and found the running light circuit is not working. There should be a large fuse box on the driver side under the hood and on the fuse legend the fuse you can check out is titled 'Trailer Park'. This is a 15 amp fuse and can be the source of the problem.

If you find the fuse is blown, you will need to find the cause. It could be on the truck wiring or a weak ground, or it could be a problem with your friend's trailer that caused the fuse to blow. After it caused the problem, your trailer would also show the same symptoms. I recommend making sure your friend's trailer has everything working correctly before towing it.

if you replace a blown fuse and find that the new fuse blows too, there is a problem with the trailer wiring somewhere on the truck. If you have a 7-way connector on your truck and are using an adapter for a 4-way, you may find the problem with the adapter.

Check for signs of a bent or damaged pin on the trailer connector. Also check for signs of corrosion and make sure the connector is clean. Next check the wiring on the truck side of the connector to make sure you are showing current when the running lights are on. If you do not show current on the connector but you do on the wiring on the truck side of the connector, then you will need to replace the trailer connector.

If you do not show current on the wires in front of the connector, you will need to check the wiring forward for signs of damage or pinched wires or possibly a wire have been severed.

I have attached a couple of links to helpful articles about trailer wiring and troubleshooting you can check out.

expert reply by: Jeffrey L