Truck shuts off when towing... 96 F250 7.3

[Andy FitzGibbon]

This is my first post.
My truck is a 1996 F250 4X4 extended cab, 7.3 PSD, 5 speed, 4:10 axles. It only had a flat four trailer plug on it when I bought it, so I set it up with a seven wire (using a factory trailer harness from the junkyard). I put in a Valley Industries Journey HD brake control with the Ford plug pre-wired on. (Got a good deal on it, that's the only reason I bought it, and it seems to work fine).
Everything works, except that the truck sometimes dies when coming to a stop or sitting at a stop sign. So far it has only happened when the trailer is connected, but doesn't happen consistently. (Trailer is 8000 lb. 2 axle dump, doesn't matter if it's empty or loaded. This is the only trailer with electric brakes I have hauled so far). It will start back up immediately, but will die again after a few seconds. It only seems to happen when brakes are applied- other than that it runs great. No stumbles or missing, only dies at idle with brakes depressed and trailer brakes hooked up. Makes me think the current draw of the trailer brakes might be whacking out the computer. Does anyone have this problem or ideas on how to fix it?
Thanks in advance,
Andy FitzGibbon

[Logan]

You could hook the trailer up and put a meter on your bats to see how far the power is dropping when you hit the brakes. See if it is pulling the volts down that far or if it is maybe something else.


Oh, and



To POWERSTROKE.ORG

[pipelayerjdh]

Welcome!


My truck does the same thing. It died almost every time I hit the brakes.
I doubled the size of the brake wire going from the controller to the plug. I still does it some, so next I will be changing my battery cables and maybe an alternator upgrade.

Good Luck!

[Ditty]

It MIGHT be a short on the electric brakes on the trailer. Maybe a frayed wire that is intermitantly hitting some metal surface. I'd check the trailer before replacing wires on the truck and battery cables. Also, check the wires on the trailer wiring harness on the truck. Might be a short there too or a problem with the TBC. (Trailer Brake Controller) It really sounds like it is something simple like that, expecially if it's only doing it when you have a trailer connected.

[Andy FitzGibbon]

Thanks to everyone for the replies. The bumper wiring harness on the truck should be good. I just wired it recently and it all tested out OK, but I will check it again. I guess it could be somewhere further up the line between the cab and the bumper.
I want to try another trailer with electric brakes on it and see if it does it. So far I have only hooked up the one trailer, so it could be the trailer and not the truck. The brake controller is brand new and came with the Ford plug pre-wired on it, but I guess it could be at fault too.
I was wondering if maybe there was some sort of factory relay or other electrical device I'm missing, since the 7-wire hookup wasn't factory installed. I don't get 12V out of the auxilary pins on the connector (for charging trailer batteries, ect.).
Thanks again,
Andy

[straycat]

---WELCOME TO THE SITE, Keep us informed of the outcome, I'm thinking trailer wiring as well---Gord

[Andy FitzGibbon]

After reading more posts here, I'm going to try replacing the CPS. The truck has other symptoms that point to that (occasional missing w/o trailer), so maybe I'll get lucky and it will fix the trailer problem too.
I read another post here where a guy hosed down his trailer attached to the truck and it started doing what mine does- apparently was moisture in the trailer connector.
Got a CPS on order from eBay, will post after I get it in.
Thanks,
Andy