I have a 2004 1500 4X4 quad cab hemi with a 7 pin wire connector in the bumper, and a 4 flat connector under the bumper. Both are factory installed. No matter what trailer I hook into, I have no right brake light or blinker. The left brake and blinker work fine, and the parking lights work fine, just no right blinker or brake light on the trailer. The truck lights all work fine. When I check the wire plugs with a test light, neither one has any juice for the right rear blinker or brake, proving the problem is in the truck somewhere. Is there some kind of inline fuse or fusible link or relay or something that might be bad that I can find and change, or am I in for a trip to the dealer??? The fuse box doesn't list any normal fuse for it. It used to work just fine, and I pull trailers almost once a week, so it isn't something I can overlook. Any help would be greatly appreciated.

 

I had a similar problem with my 03. What I found, is that the flat connector under the bumper had coroded and one of the plugs had actually broken off. I ended up cutting out the flat connector and splicing the wires directly. If you do this, Make sure you wrap the wires really well, I ended up with more corosion the following winter (darn road salt), and once again had to cut out the coroded area of wire.

Good luck!

 

So, I should be able to cut off the 4 wires going to the 4 flat connector, then plug in to the 7 pin and see if everything works ok? If it does, then I know I've found my problem. Or does the 4 flat need to be wired in for it to work? Thanks for the advice. I'll work on it tonight after work.

 

I had a similar problem with my 03' Ram their is a seperate fuse for the trailer harness , I'd check again

 

I think you'd need to just cut out the plug its self then splice the wires to the coresponding (same color) wire. Just get rid of the flat plug, its nothing but trouble. The wires that come from the 7 prong to the flat plug and the wires that come from the trucks wiring harness to the flat plug are the same color and should be easy to splice. Remember to really wrap it up well though, cuz you'll just be back under there fixing it again next spring.