Had to replace the battery on Monday, it was at 9.5 volts and would not take a charge. Alternater is around 14 (under load) to 14.7 (no accesaries) volts. battery was at 12.9ish volts when I got home from work, and 12.5ish 4 hours later. It's a slow drain, but enough to where the car probably won't start in the morning. could it be I got a bad battery? where should I start looking for the problem?

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Have you checked it again since then? Your first reading of 12.9 may have just been a bit high due to the battery just having been charged by the alternator.

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The most common cause of overnight battery drain on the pre-87's is the headlight motors. The motors will usually feel warm if they are drawing current. The alternator itself may also draw current when the car is off and still charge O.K. when running. A quick way to check this is the take the charging lead off the back of the alternator (motor not running) and see if it sparks when reconnected.

quote Originally posted by spark1: The most common cause of overnight battery drain on the pre-87's is the headlight motors.

i disagree.
i find it to be the deck lid light switch.

quote Originally posted by Xanth: Have you checked it again since then? Your first reading of 12.9 may have just been a bit high due to the battery just having been charged by the alternator.

Surface charge.

quote Originally posted by Xanth: Have you checked it again since then? Your first reading of 12.9 may have just been a bit high due to the battery just having been charged by the alternator.

I disconnected the battery over night, was at 12.6 this morning. I was wondering if there might be a short in the alternator.

quote Originally posted by buddycraigg: i find it to be the deck lid light switch.

Front or back? Is there supposed to be a light under the front somewhere? I see the switch, but no light. Does this switch just run the ''door ajar'' light on the dash? This light is on when the car is running... the new battery was dead this morning (about 8.4V)

quote Originally posted by Jeckel: I disconnected the battery over night, was at 12.6 this morning. I was wondering if there might be a short in the alternator.

Could be a leaky diode.

12.6 is a full charge on a good battery. A bit higher is ok. If the battery is holding that, and it should hold it for days at least with nothing connected, then you're ok there.

Pulling down like that overnight isn't normal.

Most likely... You have a light on, HL motor problem, or a bad alternator.

There are more notes on this in my cave. You'll need a meter with a 10 amp circuit.

It is sometimes possible to recover a battery that has been pulled really low but you have to be careful. It's really easy to boil a cell if it's done wrong. If you try to run a car with such a battery in it you can kill the alternator. (A battery below 11 volts should always be charged before trying to run the car.)

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quote Originally posted by buddycraigg: i disagree. i find it to be the deck lid light switch.

DING DING DING!!! The trunk light switch was shorting out...