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Battery Drain

2K views 9 replies 10 participants last post by  Uhile3 
#1 ·
Last week I went to start my car and it turned over slower than normal. I just blew it off that it was a little cool out and the car hadn't been started for awhile. Later that day I went to start it again and the battery was dead. I started checking things and figured out that the battery was bad, so I replaced it. Now this weekend, went to start the car again and it turned over slow. Once this happened I started thinking that something was draining the battery.

So this afternoon I started checking things out. First thing I did was pull the negative battery cable. Then I connected one prong of my multi-meter to the negative terminal of the battery and the other prong to the negative cable with the multi-meter completing the circuit. I then selected 10A on the multi-meter to see how many amps I was pulling, it showed around .50. I then started pulling fuses in attempt to isolate the problem. I eventually pulled the main fuse and the amps dropped down to .21. I continued pulling fuses until I pulled them all and the main fuse was the only one making a difference. With that I'm completely stumped. It's leading me to believe that there's something wrong with the ECM. Other than the battery draining, the car is running fine. Does anyone have any ideas? Any insight would be greatly appreciated.
 
#3 ·
I have the same problem with my monte carlo. Make sure that you wait around 45 minutes before reading the multimeter. Some things in the car need to stop charging or turn off first. I know the radio is always a culprit. .21 still is high. I'm not sure on the gto, but the monte carlo, according to gm, should be at or less than .06.
 
#4 ·
ahhaha i have the same probem as well
 
#8 ·
In another thread, it was mentioned that battery drain drops off to proper levels only if you set the alarm.
Also, I have noticed that the miserable original ignition lock cylinder sometimes does not pop out that one m.m. when I remove the key. This leaves the BCM in 'I am still in the car' mode. The radio stays on if it had been on, and the wipers still work, the windows still work, as well as the accessory plug and some other stuff. Way too complicated for a car without available replacement parts.
 
#9 ·
Sounds similar to my problem.

Just replaced a newish (didn't have warranty info to get free one) Optima yellow top, my alt tested bad on my multimeter so taking that in to be tested for sure is my next step.

But the alternator (although an ebay "220amp") added by the previous owner doesn't have more than 3k miles on it...

If its not the alternator, it sounds very similar to this.

I did check my BCM wires and found nothing.
 
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