Ok so the other night my GTA goes dead in the middle of the night 50 miles from home. Alternator obviously quit charging. Happened all of a sudden. All summer my new battery and new 140 amp Powermaster have worked fine. So I charge the battery to do a voltage test. As I suspected the voltage dropped and kept going down. So I disconnect the battery and look for some bad wires. All looks ok. Now I go back to hook up the battery( I always do the positive first then the negative) and all of a sudden everything starts coming on . Radio, interior lights ect. This was with the ground wire to the battery NOT hooked up. So I think maybe something in the alternator. So I completely disconnect. No change. All car function will operate in this condition. Not sure how to chase this one down. Maybe something I should look at? Oh And this is the third alternator I have been through in a year. Seems the bearings go out in them. Like they get cooked or something. They start to sqeel. The Powermaster made no noise. This ground thing is a new condition as earlier this year when I did put the new alternator in everything was dead until the negative was hooked up.

 

I'm not sure if I can help you, but there's something here you're not telling us.. Was the engine running while you disconnected the battery? If not then what you're telling is impossible, unless your battery somehow has become grounded on the underside.. Of course the ignition quits working below a certain voltage but you should be able to notice the lights growing dim a long time before that happens. Too high belt tension can ruin the front bearing.

 

Something I'm not telling you?? OK. Yes the motor was not running except for the intial voltage test. I think you may have misread possibly. During the other tests the engine was not running at any time. Yes I was a little stunned too. Been working with cars for years and this is the first time something like this has come up. It really threw me off for a few minutes. I still haven't gone back to look at it again in detail. When I get some more time, I'm on it.

 

Ok, so the engine was not running, you disconnect both wires to the battery, then you reconnect the positive, and all of a sudden you have power, even if you then disconnect the positive again? I'm sorry if I misread it but it's the only way I'm able to interpret what you wrote (and it makes no sense.. Well, all things has an explanation, so..

 

No, everything comes on when I hook up the positive and no negative. Acts like the negative is hooked up too.

 

maybe an exposed wire grounding itself before making it back to the negative? the battery ofcourse is draining itself since the current isnt making its way back to the battery. maybe u could check the negative line without hooking it to the battery and see if the power is even coming through the line.

 

Well, if you have nothing connected to the negative post(s) on the battery and still get power (not enough to start the car i guess...?) then pull the battery out of the car and inspect the case for damages.. Have you been mounting anything in proximity to the battery recently, using screws? Someone been playing around with a nail-gun maybe, nailing the battery?