Weird Electrical Issue: Trans/ABS/IDM Relay/Trailer Lights/No Start

HoustonPSD

New member
Joined
Dec 6, 2007
Messages
5
Here is the deal. 2002 7.3 4x4 4R100

I have recently had some troubles with my trailer plugs at the rear of the truck. The running lights work, but the stop/turn/brake and electric brakes didn't. I thought I diagnosed it as a connector with a broken tab that was allowing it to loosen. I taped that up for the time being to make sure that was the issue. It worked fine and all voltage test fine at the plug. So I install my 5th wheel in bed plug. It works fine. Park the truck and come out the next day to do some other things and decide to test the trailer lights again. Nothing. Truck won't even start. IDM relay clicking like crazy. 20 amp maxi fuse and 20 amp mini fuse blown for trailer tow. Great! Battery terminals are tight and clean. Batteries are less than 2 months old. Truck has been running fine. So I take a step back, do some searching go buy some fuses and come back. I R&R some fuses to make sure nothing else is blown (I only checked circuits involved with IDM and trailer tow, I need to check everything else tonight). So after removing the 5th wheel harness and replacing the maxi fuse and checking everything else it starts right up. I let it run a bit and shut down and fire it up again. No problem. Shut it off...wait 10 minutes and it fires up again. Now I'm back to square one as my trailer turn signals/brake lights don't work again. At this point it is dark and I go in for the evening.

This morning I come out and start it up and it fires right up. This time the Overdrive light is flashing, the ABS light stays on and the thing won't hardly move in drive. In drive it won't rev up past 1200 rpm and acts as if the e-brake is applied (it is not). In reverse it moves like normal and in Park it revs fine.

I'm at a loss.

Cliff Notes:

ABS light
Overdrive light flashing
Won't rev past 1200 rpm in drive and will barely move
No trailer brakes/turn signals/brake lights.

Any thoughts? Was supposed to take out the new 5er this coming weekend, but that is out until I am comfortable with a solution.

Thanks in advance and sorry for the novel.
 
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