Dead battery, but alrenator's chargeing

RGBCH45

MEMBER
MERCURY TRACER

I have a 1988 Mercury Tracer, and I've had the alternator checked 3 times. When I let the car sit idle for 3 or 4 days, the battery's DEAD :shock:, and I mean DEAD :, the door buzzer won't even sound. I've tried a good battery, and the same thing. When I drive it for weeks straight, it charges and stats just fine :D, but let it sit for a few days, and it goes dead :x. Ive had AutoZone, and Napa check the alternator, they say "It's working just the way it should" :oops: Now, my question is - Can it still be the alternator? People say "Yes" it can be, they say something about the regulator, and/or the diodes sticking open/closed and draining the battery. I've check all the wires that I could, battery, starter, ground wires etc. Any ideas, does anyone have an answer for this nightmare :

3 Replies

EPROSSER

MEMBER
3 POSTS

Are you postive something is not wearing down the battery while its sitting? Rader dectector, truck light, door light?

Was this

answer

helpful?

Yes

No

Friday, November 23rd, 2007 AT 4:09 PM

MERLIN2021

MECHANIC
17,250 POSTS

If the alternator has been check, I doubt it is the problem! If you have a voltmeter, remove the negative battery cable, attach the red lead of the meter to the battery post, the black lead to the cable end, with all doors shut, you should see a draw of no more than 1-2volts. If you see a high draw, anything higher than I mentioned, pull the fuses one at a time, check meter for a drop back to normal, then replace the fuse. When you find the one that drops you back to normal, that cucuit is the parasitic drain on the battery, repair that cucuit, and you will be fine!