'90 Geo Prizm GSi won't start

I think you should try using a toaster to see

if the alternator is charging @ approx 14.2 Volts.

It's a Jeep Thing.

You have some kind of parasitic load on the system when the car is off. What's been done electrically? Did someone install a stereo and wire "Remote" to "Batt." and leave it as is?

I believe there's normally a 20mA-ish load when the car is off. What you need to do is stick an ammeter in line with the positive cable (with the car off) and see what's sucking up current. Could be many things....but I'm thinking it's an accessory of some kind.

-Tim

Approximately 11/5/03 23:26, Taivas Degroff uttered for posterity:

You don't post a year, so can't guess how old your Prizm might be. Factory batteries should be replaced at about 2 years, 3 if you feel lucky, particularly in hot dry climates.

First, make sure the battery connections are clean and tight. Very clean and very tight. Also check the black cable where it attaches to the body to make sure that is also clean and tight.

That alone may fix it, as it sounds like your battery simply isn't charging all that well.

If that don't fix it, get your charging system and battery checked. Don't cost much, and they will usually clean the posts and connectors for you while at it. They should also check the key off current drain and let you know if it is excessive.