Keep Blowing 20 Amp Running Light Fuse when Connecting Trailer to 2012 Ram 5500

Question:

I have a 2012 ram 5500 cab and chassis, no matter what trailer I hook up to when I turn on the running lights it keeps blowing the 20a fuse under the hood. I unplug the trailer and replace fuse and test at plug on the truck and get power to the plug, but as soon as I plug in the trailer and turn on the running lights it blows after a few seconds. I have actually put a 30a in and same thing.

asked by: Brian G

Expert Reply:

There is a short circuit somewhere that is causing the fuse to blow. A short would cause excessive power draw. Since it only happens when you plug in a trailer it is likely that the short is in the trailer connector or the wiring to it.

You will need to make sure that there is no corrosion build up on the pins of the connector but also on the inside of the connector where the wires attach. Also check for any frayed or pinched wires touching metal and fix as needed.

expert reply by: Michael H