constant battery drain

Trail of Dead · Jun 8, 2007

I just posted a thread on my GT doing the same thing. I have NO UD Pulleys, a 200w Sony that works fine. I believe my problem lies in the door switch as the dome light would stay on, till I removed it at least, and the dinger for the key still goes off even when the car is going down the road. I tried spraying some WD on the switch itself and letting it soak but no dice. It HAS to be the switch in my case (maybe for many of you too).

SaleenGT2001 · Jun 8, 2007

the light doesnt stay on. i'll mess with it more on thursday

Mustang5L5 · Jun 8, 2007

Here's the proper way to test for drains.

WIth the car off, you typically want less than a 1A draw on the battery. Obviously the less the better, but most cars hover under 1A.

You need a multi-meter that has the ability to measure Amps in DC voltage. You need to remove the positive wire from the battery and hook the meter up in series with the cable and battery post. One wire to the post, the other to the wire.

It will now measure current draw.

If you have under the 1A, then it's a weak battery. Once they die, they are never the same and will drain very quickly if the car sits. The key is to never let the battery drain down ever. If it does, it will never hold the charge the same again.

If you have more than an amp, time to start pulling fuses and see if you can isolate what circuit is drawing.

Once you isolate a certain fuse, you can track down some wiring diagrams and see what it powers. If it's a lighting circuit, it could be a shorted bulb, or a bad socket or some other fault. Could be a wire that rubbed on the metal and is shorting to ground or something like that.

Spiggs · Jun 8, 2007

I have seen issues like this with factory GM electrical systems. nine times out of ten it turns out that the alternator has a damaged diode, or triod, but still charges the battery when the engine is running. The symptoms are a constant 1 to 5 volt draw on the battery when the engine is OFF.

screamin gt · Jun 10, 2007

smokin00GT said:
My husband has a 98 with the red top battery. His car does the same thing. He is now on his 3rd red top battery in a year and a half. Autozone checked it each time before issuing him a replacement and found it to be bad every time. I don't know why.....he has no under drive pulleys, no sterio, and no aftermarket amps.

guy at advance advised me against the yellow and red tops, explaining that he got many more of those returned bad

Trail of Dead said:
I just posted a thread on my GT doing the same thing. I have NO UD Pulleys, a 200w Sony that works fine. I believe my problem lies in the door switch as the dome light would stay on, till I removed it at least, and the dinger for the key still goes off even when the car is going down the road. I tried spraying some WD on the switch itself and letting it soak but no dice. It HAS to be the switch in my case (maybe for many of you too).

explains why theres no dome light in my car, guess I'll leave it that way

Spiggs said:
I have seen issues like this with factory GM electrical systems. nine times out of ten it turns out that the alternator has a damaged diode, or triod, but still charges the battery when the engine is running. The symptoms are a constant 1 to 5 volt draw on the battery when the engine is OFF.

bingo, had the problem for years with my wifes firebird, replaced numerous bat. and the alternator, and the alternator (new) was defective(charged but only 10 volts instead of 14). replaced again. problem solved...... I think

constant battery drain

Trail of Dead

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SaleenGT2001

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Mustang5L5

That is…until I whipped out my Bissell

Spiggs

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screamin gt

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constant battery drain

Trail of Dead

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