Ive been towing my car trailer for about 3 years, and it recently got to where the right side blinkers and brake light does not work on my trailer. I know its not my trailer cuse i hooked it up to another truck and it did fine. Ive tried both factory connectors on the truck and neither will work. Any ideas on what it could be. Oh and i have an 04 1500 ram hemi quad cab.

You should check the truck side wiring for your trailer wiring.

Any grey or green connections will increase resistance and cause problems.

A good spray contact cleaner on the plug connector and then diaelectric grease helps a lot.

Good luck.

If everything on the truck works and the trailer works on another vehicle it has to be a plug/connection somewhere.

There is a specific trailer light fuse in your fuse box. I don't remember the number but it is on the back row closer to the firewall. I made Lowe's order me 2 enclosed trailers before I figured that one out. OOOOOOPS My bad

See my first thought was a fuse, but i pulled every single one out and nothing. My next step is to replace the plug cuse tryying to find the bad wire will be alot harder. Thanks for all the info guys, Ill try the cleaner and see if it helps...

I had the same problem on my old truck. Try checking all the connectors to the truck side of the plug. Mine had come loose (cheesy factory crimping at the plug). I just had to re-do the plug on my trailer due to the same type of issue.

Thanks Fritz, Ill double check that while im down there..

i had this issue. check the power at the connector, the trailer harness on these trucks runs strait to the fues box, the brake and turn for the left and right on the trailer are controlled by a fues then a relay, the fuse is replacable, the relay is NOT. its built into the fuse box, and you have to replace the whole thing to fix it. pull the fuse cover and turn your flashers on. you can hear the relays. they should sound the same and mostly in sync. if ons bad it will be obvious if they sound different. i also pulled the fuse box apart, no way to replace just the relay.... shitty design!!!

i tried bypassing this and wiring in a tail light converter, you have to completly rewire the connector to get this to work as , at least for me, the tail light convertor caused a voltage drop. when i wired in only one light, the running lights that were still coming from the fuse box would over power the brake and turn, and defeating my would be fix.

Yeah I have still not been able to chase this problem down. I dont wanna take it to a stealership to charge me a ton to install some crap that may or may not work. Im thinking about just splicing some wires to run off my tail lights since i dont use trailer brakes I dont see that being a big issue.

On my truck the right and left signals work on the trailer but the right brake light does not. Does this sound like that relay you can't change ?? If so, how hard is it to change that relay center ? Is it just a matter of unplugging the old one and plugging the new one in ?

no, the relay is only for the turn signals. and only one brake light working and not the other is your trailer. the plug in on the truck cant distinguish left and right brake lights, it either works or it doesnt.

if you run a tail lamp out converter it will drop the voltage. tried this a while back to get around the fuse box issue lol. the running lights ended up over powering the turn and brake signals.

fix is easy enough, just swap in a new fuse box, buttttttttt they cost $300 bucks

These trucks have a converter built in, and if the turns are working and 1 brake light isnt its deff the fuse box workings inside, try to get one at a salvage yard, might be a quick fix for sure, you can also go get the tail light converter that has a power wire going into it so its not runnin resistance and overpower wires for the turns

The fuse box should be the same for all 02 06 models right ?? I try to get this answer out of the dealer, I get a different answer every time.