I have a 2003 ho ctd with a 6 speed. For some reason, my left turn light wiring on the truck is dead. I thought maybe something had come loose at my 7 way. I have the stock setup on the bumper and another added to inside the bed for the gooseneck. Neither works and as well I used a test light at the loom of wires from the main harness under the rear end. No fuses are shot and I am not sure how these relays or flashers work with the blinkers. Has anyone had this problem or know what I need to look for? I need to head out tomorrow with the trailer and need to get this issue fixed in the morning if possible. TIA...

 

You could have a short in the wiring on the trailer..

 

The trailer has been disconnected. I am just testing the leads off of my 7 way connector and the main harness under the truck. I cannot even get a signal coming out of the main harness. I cannot find anything else wrong.

 

did the problem accur with the trailer connected or disconnected..?

 

If the trailer is disconnected i wouldnt know what to tell you except for a short to the rear light or light might of gone out

 

Pull the fuse and use your tester to see if you have any juice up to there. If not I would bet on the switch in the steering column. If you do have juice that far then you then you just have to trace the wiring and test it along the way to see where the break is. Since this is the only bad component you have grounding problems are pretty unlikely. Most of it is on a common ground so it would affect several things.

 

check for a short in the wiring at the trailer connector itself... the pins are sort of close together, and may rub through.

 

This is definitely on the truck side of things. I have to 7 pin connectors on the truck. Neither one is working for left turn. I thought the same thing about the plugs. I have went under the truck followed the wire loom back to the factory dodge wires and checked for signal there and still nothing. The white with pink stripe wire is for right turn and is working correctly. The yellow with pink stripe wire is for left turn and I get nothing with the test light. My problem is for sure on the truck end of things.

 

Do the left turn signal bulbs on the truck work? Do they flash normally?

 

My guess is either the fuse for the trailer tow left side or the relay is dead. On a 2004, it's fuse #46....don't know if that will help you.

Open your Power Distribution Center and read the fuse and relay list. Check the fuse first. If the fuse is OK then swap the trailer tow left and trailer tow right relays and see what happens.

 

The fuses are good. How do you know what relays run what? None say anything about right/left turn for trailers???

 

I just went out to my truck and couldn't find the relays in the PDC. So I downloaded the 2003 shop manual from hemitruckclub.com to see if there was anything different in the wiring diagram. There wasn't.

Sorry but I don't know where those relays are. Maybe they are stuffed into the Front Control Module (which I'm not sure if that is user servicable). I'll keep digging around to see if I can find anything.

 

I'm pretty sure there's a relay in the underhood box for each left and right signal for the trailer circuit. Turn on each signal light and listen under the hood for the relay to click. If you can hear relays click for left and right, you can identify each relay, and start your diagnosis from there. If only the right turn relay clicks, hopefully you can use it to figure out where the left one is. It's pretty rare for a relay itself to fail, but the relay is almost always the best place to start diagnosis, because 4 circuits come together right there to make the system operate. You need to find out which of the 4 circuits isn't working.

 

Well, It looks like the fellows at DC were nice enough to bury the relays in the front control module. This means if you ever have a problem like mine you will be heading to the dealer more than likely. You have to seperate the 2 panels of the fuse box to get to them. Guess what they are plugged into... The ecm. Basically the motherboard and processor of the truck. Something I am not willing to risk fooling with. I will be raising some sand with my dealer on this one. That is just a horrible design.

 

OK. I have my lights actually working now but I had to cheat for right now. I spliced into the left turn signal wire going to the turn signal on the truck. Running a jumper from there to my 7 way has my lights working again. This is temporary though. I hope I can figure out why I have lost my left turn signal off of the trailer tow package.