My 1996 standaard Saturn SL1 (gold, with 113,000 on it) has had two new batteries in the last six months. It continues to die if I don’t run it for a day or two. The mecahnic put in a new serpentine belt, but that didn’t solve the problem. After its last jump start the mecahnic said it was draining the battery but he couldn’t figure out exactly how. He suggested it could be a problem with the starter not turning the car off completely, though appearing to do so. Any ideas?
Usually this is not too hard to find. Something is likely draining the batter when the engine is off. Look for the easy stuff like trunk or glove box lights. Then get a tool to measure CURRENT (not voltage) from the battery and hook it up with everything turned off as it would normally be when parked over night. Now start pulling fuses unit it changes. Record how much of a change there is for each fuse. Come back and post the results, or if you mechanic is doing this he should have a good idea what circuit is the problem and can go from there.
Note: There are a few odd things on a car that might not show up until the car has been turned off for some time. In that case you may need to monitor the voltage over night and repeat the test if the overall drain increases at some time.
I very much doubt that the starter circuit is causing the trouble but there are other things that are suspect, the alternator circuit is one of them along with others that have power tied to them at all times. It sounds to me that your mechanic isn’t very savy on electrical problems, which is pretty common. I would suggest you take your car to a place that specializes in repairs of electrical trouble. They will do a test like JEM described in the previous post and track down the trouble.