EDIT: Problem has been solved. Go to post #7.





My car has been having issues with losing power after the car sits overnight. The battery lost all its power so I had autozone charge it and test it. It charged and tested OK.

Yestarday, I used my multimeter to see how much power the car was drawing just sitting. It was ranging from 15-35 mA. The battery was putting out a little over 12 volts terminal to terminal. With the car running, it read 14.X (I can't remember the exact tenth).

Now this morning, I go out to the car and its completly dead again. I have also been having issues with my alarm system. It doesn't make a loud chirp from the siren when I lock or unlock the car. Maybe the siren is bad. This has been ongoing for months so I don't think it's related.

Another problem that started a week before my battery died for the first time, was my subwoofer stopped working. I have yet to diagnose the problem there, but it seems the amp kicks on/off with the cd player as it should.

Any ideas? I'd like to get this solved before snow comes. Thanks.

 

generally thats a sign your alternator is going

try charging it, running it, and when you shut it off...disconnect the alt.

see what happens.

 

Are you saying charge the battery (it's dead right now), then remove them alternator, then hook the battery up, and see if it's dead a few days later? Or do you mean just unhook the connections to the altenator?

 

Apparently the newer cars and computers in the cars do not like the old way of unhooking the battery to see if the car will run just off an alternator. I probably would do it anyway haha. But as teke184 said, try disconnecting it after your car is off... maybe something is shorting or drawing from there?

If you can drive with the car running and its fine then I wouldn't think it would be the alternator. The alternator charges as you drive or else your car would die when your driving.

What I would do is, check the amperage draw like you did by disconnecting the positive lead on the batter and hooking up the multimeter in between the battery and battery cable.
Now, I would start by pulling your airbag fuse because you are messing with electrical and you dont want to set off those bags. (Here its a grand to repack each bag so thats 2 grand plugs cleanup)

Then with a friend watching the multimeter, start pulling fuses till you see the amperage drop a lot. If it might be stereo related, start pulling those fuses. Radio, accessory, amp fuse on the amp...any aftermarket setups like the amp wiring that may have a fuse to the battery directly... go through them all. Im sure you will find the problem fast.

You shouldn't have much of a draw... just enough to run a alarm if you have one and small stuff likes clocks etc.

Oxy

 

one more thing, try disconnecting your amp and sub over night. You say your sub is messed up? Maybe its drawing some how, I highly doubt it, you should hear something like fuzz but I have see and heard stranger things... haha

 

Any luck with this problem?

 

I appoligize for not answering a while back. I put the car away for the winter because it was getting too cold to be out there diagnosing the problem.

It turns out that the sub failure was what was causing it. I just figured this out about half an hour ago. It was pulling over 1/2 A with the amps hooked up, and when we unhooked the sub amp, it dropped to about 20 mA. Thanks for any advice that was given. Now I just have to get a new amp. A few days ago sears gave me a new battery too, so I'm pretty happy.

EDIT: we took the amp apart and sure enough, something inside got cooked.