I went to pick up a new utility trailer today. Hooked up lights, and brake and signals worked. Turned on headlights, and nothing will work with headlights on. Trailer guy says they have had this happen with Dodge trucks before, and something had to be reset. Phoned my dealer, and they said the "scanner has to be used to reenable the control module". Has anyone else heard of this?(PMO)

 

Ted, I've got a 2005 QC, CTD, 6spd and towed my brothers trailer to Denver from Ohio and never had the first problem with the lights. Sounds like someone may be grasping at straws. Then again, all this computer control stuff does "wonderful" things now and then. Keep us posted for future reference. Thanks, Lektrikman

 

There may be more than one thing that could have happened. There is a reflash for the tipm to raise the amperage allowed on trailer lights, or there is actually a problem with the trailer lights that has kicked it out. If you're under warranty, see the dealer. If you aren't under warranty - see the dealer! They are the only ones who can reflash the module, and I suspect that will cure your trouble.

 

I've towed my 5'th wheel for 2 months without a problem, but the service manager at the dealer, and the trailer guy both told me the same thing.???

 

Is that reflash for the 05's as well?? (Truck is under warranty, and trailer is brand new.)

 

My bad....it is for 06 trucks. BUT! I have seen more than one truck that had a newer module in it than supposedly was available for that model year. It defiantely worth a trip to the dealer. How many lights on the trailer? Are the fuses o.k. under the hood? Do you have the separate FCM bolted to the side of the fuse box? It will be visible between the fuse box and fender. Thin silver box. If so- the flash wont help. If no silver box on the side of it - the flash may help. Do you know the build date of your truck? Like I said, some of these things were running changes! Could there be a possibilty that the wiring in the bed is at fault? Does it work on other trailers?

 

It's an early 05. It has the separate FCM. Service manager knew this. He said to unhook the batteries for 3 minutes, and it should reset itself. I tried that, and it didn't work.

 

SO ......when the brakes were pushed, everything quit? Sounds like it blew the trailer fuse. There are seperate left and right lamp fuses and also a larger fuse just labeled trailer.

 

Fuses are fine. Without the headlights turned on, the brakelights and turn signals work on the trailer. When I turn on the truck's headlights, the trailer brakelights, turn signals, or lights on the trailer will not work.

 

Sure sounds like a ground problem to me. Hard to say when I'm not there, but I'd say the fcm is doing it's job. If everything comes back when the lights are turned off, something else is going on. Get a set of jumper cables ( real redneck trick here! ) and put the ground clamp on the frame of the trailer and the other end on the frame of the truck. You know, wiggle them around to get a good ground, and see if it makes a difference. It takes a lot more juice to run all the marker lights and all compared to just the brakes and turns and that will make a poor ground show up.

Also...... bumper pull trailer? 5th wheel? Gooseneck? Factory wiring? 7 way? 4 way? Factory 7 way and 4 way adapter? Just need some more to go on.

 

Bumper pull trailer (2 inch receiver). 7 way plug, but only 4 wires.

 

Try the jumper cables. I'll bet it is a poor ground on the factory wiring for the trailer. Probably didn't clean the paint off where they grounded it. Some trailers will get ground thru the ball, but not a great ground. Especially on a new trailer. They usually have grease in the ball cup.

 

it sounds like the brown (running lites ) and white (ground) wires are crossed. everything is using r/l lights as ground until headlites are turned on then it directly to ground. unplug trailer if all lites on p/u work you have wires crossed. trace out wireing and all should work.
Good luck

 

I had the scan test, and 7 way plug checked on the truck, and all was good. I phoned the trailer people, and they still insist it is my truck. I asked them how it is grounded, and it is only through the trailer ball. I pointed out that my receiver is still painted inside(I pull a 5'th wheel until now), and my drop hitch insert is brand new(painted)- so how can I get a good ground when more lights are turned on? I ask if they can ground the trailer plug to the trailer frame(1 wire!). They say- the problem is with your truck!! I'll pick it up and do it myself. Thanks to all for your advice and help!

 

I'm not trying to be rude, but try the jumper cable test to be absolutely sure. Then you can add your own ground thru the 7 way connector on their ( junk if it has NO ground!) trailer! LOL Just kidding, but come on! Why not put a simple ground wire on a brand new trailer? Can't cost that much more when they are building the dang thing.