This was great advise. I switched my fuse from one factory fuse to another and still had no power to running lights. Read this and stuffed foil into fuse area checked for power at foil location and had power. Went back to 7 and 4 pin harness and have power now in both harnesses. I guess now I just need to replace all of my 20a factory fuse in my 2014 Ram 3500.

 

I have 2017 Ram 1500 Laramie and the right trailer fuse keeps blown when 7 pin plug is plugged in. I used another 7pin plug with pigtails on it and it still blows the fuse when its not connected to trailer. Any ideas to solve problem as it blows fuse right away

 

Which fuse is it blowing?

 

Its the 20 amp right tail light fuse in fuse box

 

Any warranty left? Does the fuse blow ONLY when the trailer is plugged in, regardless of if there is a trailer?

 

Put a multimeter on it and probe the terminals to see if it's getting power. Then you can determine if it's a problem with the truck or a problem with the trailer. Just a quick YouTube search, this may help you out