I have a 98 model half-ton with a 318. Something is draining the battery when the truck is off. All the battery connections are good, and I've removed the fuses from the sound system, and that didn't fix anything. Do you guys have any idea what the most likely cause is?

 

Disconnect one of your battery leads. Put a meter, or, if you don't have a meter, just use a test light, between the cable end, and battery terminal. (set meter to measure amps. 10 should be adequate to the task.) Start pulling fuses/relays until the draw disappears. That will tell you which circuit you need to start looking at.

 

Have you had the battery load tested to make sure it is still OK.
Doesn't matter how new it is... there are batteries and then there are batteries.

Otherwise, previous post is a good lead to follow.

 

Years ago I had this kind of problem on a Plymouth Voyager and the problem was the circuit in the radio that was always hot to power the clock. changed the radio and all was good.

 

When i first got my truck the light under the hood stated on would not shut off. It use's a mercury type switch.

Dave