2012 Dodge Ram 1500 trailer running lights not working

[GaryB66]

After much research here and YouTube it didn’t help. I had stop lights, bother turn signals but no running lights to my trailer. Picked up a plug in tester and confirmed it’s the truck. I pulled out the 7 pin/ 4 pin factory installed plug. Pulled everything apart cleaned it all with WD40 And put back. Still not working.
Research showed the running lights are on a separate circuit with a fuse. The problem is there about 4 fuses listed in wiring diagrams showing parking lights. All looked good.
Then as we tend not to do I looked at the manual. It showed a different fuse J14 which is a large square fuse 20 amp.

It’s hard to visually see if burned out so swapped it with my washer fuse J21 temporarily and the trailer lit up like a Christmas tree. Now to track down one of these fuses. Doesn’t look common to me. Canada Canadian tire or Lordco

I am so happy as that was a lot of headache. I started to rewire my trailer thinking it was the problem

Hopefully it helps someone

 

[turkeybird56]

20 amp cartridge fuse. Autozone has them, O'Reillys, maybe Advantage. U have to take what U have and compare. I keep several extra in a box in my truck. Tho it should not be like this, here is a hint> My 2019 has a bad habit of blowing the running light trailer fuses when I plug in, if I have the truck running/lights on. Prob a short on my trailer, but I always plug in 7 pin when truck off/shut down, no lights on.

Now since U in Canada, I am not that familiar with what stores U have up there.

 

[turkeybird56]

Canadian Tire shows they have them. Any close to you or can you call and order and mail? Since U in Canada? Best I can tell you. Once you find a source, highly suggest you get a bunch in each size, and specifically those 20 amp as any short in trailer lights will blow that fuse every time.

 

[GTyankee]

what i did was to buy 1 fuse kit that has a Tester in it

I like the BUSSMAN & Littlefuse fuse testers

 

[GaryB66]

All great advice. Canadian Tire and Lordco up here for them. There was a Dodge Package of all the fuses and cheaper to buy that way. Now a bunch in my center console.

 

[2003F350]

what i did was to buy 1 fuse kit that has a Tester in it

I like the BUSSMAN & Littlefuse fuse testers

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This tool is a game changer - I used to have no issues with the bigger fuses, but now with the micro and even smaller fuses, I can't get ahold of them without needle nose pliers. This tool doesn't damage the fuses as easily.