Slow drain on my battery and my confidence!

saturn
batteries
sc

#1

I have a Saturn SC 2, 1999, with a new battery. I had a systems check done and the battery, charging system, and everything else checked out OK. The problem is, if it isn’t started within roughly 24 hours the battery is drained enough to not turn over the engine. If it isn’t jumped and just sits there, the battery goes slowly dead. I’m sure it’s a slow drain but what is the best way to find the culprit?


#2

You have to disconnect the battery negative cable and connect a VOM or test light in between the battery terminal and the cable end. This will provide an indication of whether a voltage draw exists or not. Checking for a voltage draw (but NOT the actual diagnosis and repair) should be part of every electrical system check.

Some draw is normal (ECM, clock, etc.) but generally speaking the draw should be down under a 100 Milliamperes.
If a draw exists then you need to start pulling fuses one at a time until you determine which circuit is the questionable one. After that, it gets deeper by trying to located the actual cause and unless you have a wiring diagram (a good one, not any of that Chiltons garbage) and some electrical expertise then it can be very dificult.

The above is a worst case. What you might do in the interim is make sure something like a trunk light is not staying on, a la does it really go off refrigerator light.


#3

Thanks. I’m thinking it’s the door locks. I understand the inside fuse box is in the passenger compartment to the left, in the console? As far as a diagram, I can’t find one plus I’m no electrician.