Trailer wiring question

[tbrudder]

Hello, all.



I recently purchased a 1999 2500 QC NV4500 4x4 long bed, and I couldn't be happier. I'll never buy a gasoline engine powered truck again. And this forum is a treasure--best $35 I spent on the truck yet.



Anyway, I have a few questions, but I'm moving soon, which will require a trailer, so this one is foremost on my mind. It would appear that my truck had the factory tow package installed. I can see where a 5th wheel was mounted in the bed, and the holes where a brake controller used to be mounted in the cab, but these didn't come with the truck.



The Mopar tow hitch (500/5000 lbs weight-carrying) is installed, so I'm good to tow the 12 foot van trailer I need (I'm almost embarrassed to admit to towing such a small trailer here, after some of the things I've read), but I am concerned about the wiring.



It would appear that the factory wiring harness was not installed. I'm not really sure why--I found the connector for the brake controller up behind the parking brake, where I read it would be, and the PDC has the trailer fuse and relay, which led me to believe that the factory harness was in place. However, I found a couple non-OEM wires that had been cut behind the dash that I believe led to the brake controller (they run back to the back). More troublesome than that, all the wires for the (non-Mopar) 7-wire connector back on the hitch have been connected to the tail and brake lights with splice connectors.



Aargh!



I don't want to burn out my headlight switch by putting all those extra lights through it, and I can't understand why it's done like this--all the tow package seems to be there, except for the trailer connector.



Anyway, coming to the point, I seem to recall reading somewhere (though I've searched for it on the forums, and can't find it anywhere now) that there was a connector for the factory wiring harness somewhere on the driver's side, back near the wheelwell. I'd like to make a connection there, and clean up this hack job that the previous owner did, but I just can't find it.



Is is just hard to find, or am I going to need some kind of wiring harness from DC? Any other suggestions? Wiring my own with relays and whatnot doesn't bother me (I'm an engineer, and I know how to run a multimeter), but I'd rather use what Chrysler provided, if possible.



Thanks all, I've had a number of my questions answered already, just searching the archives. Here's hoping someone can point me to an answer on this one.



--Ty

 

[csevers]

On mine 99 the trailer connector outside the vehicle is behind the drivers front wheel well liner near your were your feet would be, I think all the trucks have this but it may not be hooked up inside the cab. I have had 2 of the my previous trucks I had the trailer lights hooked up through a "Hopppy" T connector on the tail light circuit putting all the load on the head lights switch, with 6 marker lights and 4 tail lights on the trailer with no problems but it is not the best idea.



Craig

 

[Bob4x4]

Ty,

There is an accessory trailer wiring harness available through D/C that includes a relay for the running lights. It is an easy install and a clean set-up. It sounds like someone robbed the wiring off the truck before they sold it.



Bob

 

[bombero]

Boy you have a dandy there. From what you have said i would suspect that the truck didnt come with a tow package. If it didnt have a 7prong sidways plug attached to the reciever hitch that is a big clue. Anyway i think I would start completely over. Take out those !!! splices and get a good brake controler. Buy the kit for connecting into the rear wiring and hooking up a RV 7wire conector. Dont plan on using anything under your dash that looks like it was part of a factory tow set up. run new wires. You can even by pass the light switch. Hook up the trailers running lights off a toggle switch. I did that on my 92 CTD and worked great. Good luck

 

[cwienenga]

lighting

another option I'm doing gradually is replacing trailer lights with led's. an example-the thin lights on sides,regular draw . 6amp,led . 06amp. you can run the whole thing with very little draw. they also have 1157 led bulbs now for the tailights. initial cost is high but last a long tiime.



cliff

 

[tbrudder]

Thanks for all the responses.



I'm starting to think that the truck didn't have the trailer tow package after all; maybe the previous guy just bought the hitch receiver from the parts department, and tried to save money doing the wiring himself. :|



Anyway, I found the connector I think I'm looking for (C129, I believe, on the bottom of the body, right behind the front left wheelhouse). I can see the blue wire for the electric brakes from the under-dash plug going in, but it doesn't continue out to the rear of the truck.



On another site (Fritz's, IIRC), I found that there should also be an orange/black (I believe) wire in the same connector from the trailer running light relay. I haven't had a chance to crawl under there again, but I suspect it might be there (since the PDC does have the relay in place). If so, I might try pulling the connector apart, running the wires I need for the running lights, e-brake, and +12V up from the back, crimping some terminals on them, inserting them in the rear part of the connector, and putting it back together. Make it all nice and neat.



Anyone see any problems running the turn/brake lights off splices from the existing wires, like it's already set up?



Thanks again, all, and I'll let you know what I find out.



--Ty

 

[ISBPilot]

Not sure if this is for all or not.........

My 99' is a cab and chassis model. I hooked my brake controller up to the harness under the dash and my trailer plugs (rear of dovetail and driver's side of headache rack), are wired through a harness that was located inside the rear of the driver's side frame. It is not the harness for the truck lights. It was in the same loom but continued to the end of the frame and stopped, with wires available for all plug connections. Not sure what package this indicates. This will still run your trailer lights through your regular harness, but I am planning on rewiring to heavy duty relays in the near future to correct this situation. Good luck and happy hauling.



Todd

 

[tbrudder]

Well, I finally got it figured out. Actually, I figured it out a number of weeks ago, but I just now got settled in from moving so I can write about it.



Basically, it would seem that even though my truck didn't have the trailer tow package (just a Mopar hitch, I'm thinking), the front end of the wiring harness was still in place. I'm going to go so far as to assume that all trucks are wired like this. Checking my PDC, the trailer fuse (40A, IIRC) and relay were in place. Using what I read here, and some info from the dodgeram.org site, I found that the wires for the trailer running lights, electric brake, and B+ ran down to one of two connectors (C128 & C129, I believe) located at the very back-rear of the engine compartment on the driver's side, just about opposite from where your feet are on the inside. The rear part of the harness does not carry these to the back. I just tapped the wires I needed on the front side of the connector (I believe brake was blue, running lights orange/red, can't remember B+--maybe black) and ran wires along the wire loom back to the connector, and re-wired the trailer plug.



Towed a good 800 miles with the lights on, and no problems--dimmer switch was no warmer than usual (not that I was worried--I checked the circuits with a meter beforehand, to make sure they really were isolated by a relay).



Thanks for all the input!



--Ty