Hello, I have a 1999 Ram 2500 diesel that I have been fighting the battery drain issue. After reviewing some of the previous suggestions, I have isolated the issue to my Transmission circuitry. When I remove the 10 amp transmission fuse in the engine compartment the drain goes away. It actually goes down slowly like a capacitor is draining. Does anyone have an idea of what I should be looking at? I have examined wiring as best I can and my Chilton's manual doesn't have any of that wiring in diagrams. My temporary solution is just to remove the fuse every time I park for the night.

Any suggestions would be appreciated.
Thanks!

 

Grab the 01 service manual from here. (Not sure if the links in the FAQ section work at this point, but, there was a thread here in the tech section that did....) Wiring diagrams in there will be MUCH closer to what is in your truck.

The trans shouldn't even be getting power with the key off. Try swapping the trans relay with the horn relay... see if that makes a difference.