MikeyT

Just returned from holidays and I've got some issues. Most serious was my TC slipping while climbing hills, but I've got that covered with new BD parts.

A less serious but very irritating problem is the loss of my left turn signal and brake light on the trailer. I initially figured it was a burned out bulb, but replacing it had no effect, and while I was at the campground I plugged in to another trailer to confirm the problem was my truck and not the trailer wiring.

I had the truck in to a hitch shop and they were unable to find anything wrong with the actual wiring or connections, so now I'm totally stumped.

Has anyone else had this problem? The hitch shop suggested I may have to replace the entire wiring harness for the trailer lights but that seems a bit extreme.

MikeyT

Ok - I should have done some more searching before posting - looks like this is common enough and I'm going to need a new IPM. Crap.

How easy is it to replace the IPM if I order a new one from the dealership? - is it just plug and play or will it require a flash or any more complicated installation? I have no real electrical experience.

dieselpwrRam

I had a problem very similar issue. I was getting ready to pull my cargo trailer for a trip to Tucson. I did a lighting check after hooking up the trailer. The r. rear brake and turn tail light would not work. I replace the bulb it still did not work. Then I noticed the r. rear tail light on the truck was also out. OK, this was odd. then I remembered some time back I found the problem was the switch at the brake peddle was the problem. I reached under the dash and wiggled the switch unit and made sure it was tight. I checked the tail light. Bingo all was normal again.
I went through same steps this time. Eureka, my truck and trailer signals were working again. I concluded the switch/connection was jarred loose either by my big foot or road vibration.
This all makes sense. The brake and turn signal uses both filaments of the bulb. Maybe your issue could be the same. Good luck

MikeyT

Doesn't seem to be the same problem - the lights on my truck work fine, it's just the trailer lights that don't work, and only the brake/turn signal on the left side - the running lights come on.

I'll double check though - can you describe the switch that was loose or is it pretty obvious once you get under there?

dieselpwrRam

The brake switch is is under the dash upper area of the upper brake peddle shaft, at least for my year truck. Other than the specific problem in my last post I had a loose connection at the lamp connector. My trailer wires were not loomed in a conduit being exposed under the box . This made the wires susceptible to the elements and damage. Anyway hope you trace down your problem. I not sure how different the basic wiring is between the 2nd and 3rd generation trucks. Good luck.

MikeyT

I just ordered a new IPM. They're back ordered with no indication of when the module will be available again. I guess the summer trailer season has put a run on these parts.

budmanozzy

Is that the same as the fuse box under the hood. I have the same problem and was told that I have a bad relay in the box. I have no power on the pin on the trailer plug that controls the left brake and left turn signal. Could you cut the wire going to that pin and splice in into the wire on the truck turn signal?

MikeyT

Yes - same thing. See the 'Beat the Box' thread also.

Update: I cancelled my oder for the full IPM - which includes the fuse box and FCM, and ordered just the Forward Command Module (FCM), which is the silver box that attaches to it.

Apparently the FCM is the part we need to replace, not the entire power center.

As to splicing the wire directly to your turn signals, that would work but you could end up drawing more amps than rated on that circuit, and you may dim your truck lights or start blowing fuses.

budmanozzy

Thanks for the info.

nsxt

MikeyT -

If a new FCM fixes your problem, I'd like to have your dead FCM to disassemble and see if it is repairable.

Purplezr2

I have the same issue, but have a 2nd gen truck, would I be having the same issue or different.

MikeyT

No problem - if this works I'll ship the old one off to you.

CatDiesel_762

Before replacing the FCM try having the dealer reset the FCM for ya. I believe there was recall out that metion that the setting was set to low and would requre the ECM to be reflashed to 17 volt (or amps). You can check it out here...

http://dodgeram.info/tsb/2006/08-021-06.htm

Shawn

RAMRODD

My problum is always the conection between the truck and the trailer cord. If it is plugged in all the way some stuff will work and some wont. Pull the cord out and everything comes on.
You stated that the trailer shop couldn't find anything wrong with the truck. So does that mean that their is no power at the trailer plug for the turnsignal and brake light, or your truck checked out fine and thier is power at the trailer plug?

A friend of mine changed his 07 over to the style of plug that semis use and has had no problums since. This is the route I am going to try. Right now when I plug in my trailer if I push the plug in all the way I have lights and no brakes, Pull on the plug out and I have brakes and no lightes

MikeyT

Ok - I finally changed out the FCM after having sit on my parts shelf for a couple months. No Change! This didn't do a thing.

I hadn't seen Shawn's post before changing the FCM so I'm going to go have it flashed next time I'm near a dealership and see if that helps.

nsxt - I sent you a PM earlier today to see if you wanted the old FCM, but now it looks like there's probably nothing wrong with it.

Stay tuned.....