Is there a standard method to troubleshoot this? I may have once known but it's been awhile. Part of the problem is I can't just guess and try things out because if I'm wrong I have no juice the next morning!

The battery and alternator were new in the summer of 2000 - a new (not reman) Delco alternator and 7yr Professional Delco battery. I'm not the best at arithmetic, but I think it's only been 3 years. This past winter one night the car lost all power - completely dead the next morning. I charged it up and disconnected the battery for cold nights and left it hooked up for warm nights - no problems. Since winter I've left it connected, but a few nights ago I guess it got cold enough to drain her.

There is no problem when the car is running, although I suppose my alt might be working too hard which is not a good thing. I have no idea what could be draining it - it seems very random. The most likely offenders:

1.) Since my stereo/amps/cds were stolen a couple years ago, I now mount my deck behind the passenger seat and take it in the house overnight. I wired it up and connected both the ignition and battery wires to a (fused) battery constant. This was at least 2 months before the first battery episode.

2.) I made the mistake of letting my sister borrow the car once and she broke the rear hatch motor - could it be somehow draining power? If it is, there is no light or sound coming from that area.

Thank you for any help or advice - I've got several Iroc projects to do but this is the most pressing.

Car info:

1989 Iroc-Z 305 TPI
Still strong at 153000 miles
Let's keep hope alive...

 

Ok I found an article that says I can connect a test light in series with the negative terminal on the batt and disconnect fuses to test where the load is from. I'm going to try that - but replies are still appreciated. Thanks!

 

Ok the drain is going through both the ACC and the LID fuses. Anybody know of any common offenders? It's not the lighter socket since that has been disconnected for years due to a short...

 

I prefer a test meter like a Fluke. With the car off(don't forget the underhood light must be out and all doors closed) on a 10 amp scale insert the meter in series with either battery lead. Parasitic drain should be <15ma. Pull fuses to eliminate high current draw for isolation of problem.

 

It was the hatch - in the Helm schematics I noticed that the hatch goes through both LID and ACC, and sure enough that was it. I uplugged everything and just cut the remaining wire. Eventually I'll have to shell out the 100 bucks for a new one. I'll need a vm soon in case I need to do any hardcore elec. work. Thanks.