Should I take this to pep boys or to a regular mechanic? I don't want to waste money taking it to someone who will not be able to fix the problem but still charge for diagnostics. Here's the story. 95 z28 by the way.

1.) Take car to best buy to put car stereo in, Head unit, 2 amps (800 rms total)

2.) Pick up vehicle, drive about 10 miles and ABS light comes on.

3.) Take the car to a empty parking lot to tune it up and notice that the windows are going down a little slow, but go on any way. I open the trunk mess with the amps, close the trunk and the car cuts off simontaneously when the trunk slams. Car starts right back up, notice the low voltage on the gauge, take car home.

4.) Purchase new battery. ABS light goes off for about an hour then comes back on.

5.) Uninstall complete audio system, HU, amps, everything, remove grounds and amp wire going to battery. Same thing. Still killing battery.

6.)Take the car to autozone, to test alternator, they said it's bad, so I put a brand new 140amp alt in right there on the spot and they said I was still only getting 11volts or so that I must have a short somewhere.

7.) Go home and just looking at what else it could be, I opened the trunk and pulled the remote wires from the amps, closed the trunk, started the car and MY VOLTAGE METER WAS showing good voltage, almost 3/4 mark instead of in the red. So I shut it down, start it back and still good, so I shut it down again and tell the wife follow me to best buy to drop it off. So I get back into the car to start it and the voltage meter is showing in the red again so I go open the trunk and the remote wires were close but not touching, I spread them apart, shut the trunk and start, and voltage was good AGAIN! So I drop it off at best buy for the guy to look at the next day when he came in.

8.)Call the guy at best buy and he says that it's reading 10 volts. Says that because I unhooked the amps that it voided my warranty with their install but said it would cost me 15 bucks for every 15 minutes he spent trying to troubleshoot the problem. I said don't touch it I'm coming to get it.

9) Last night I went through every fuse pulling each one to see if the voltage would rise while the car was running. I chased every wire that they put in looking to see if they may have put a screw in it or something. But no. I've had problems with my automatic trunk release making my trunk open on occasion without me pushing the button, so I unhooked that, slammed the trunk a few times, still can't get the voltage back up.

Is there anything that you guys can think of before I take it to a shop? The battery cables are tight, alternator cables are tight. I just don't know what else it could be. Would pep boys be the best place? Should I ask the mechanic is he going to charge me if he doesn't fix the problem? Thanks again.

edit:

10. I took the new reman'd alternator off and had it benchmarked and it is fine.

 

Electrical problems will challenge the best of shops. Pep boys is NOT the answer. Anywhere you go will charge by the hour whether they fix it or not. I would start by tracking down the power leads that the idiots at best buy connected and remove them entirely from the source. Not just the devices they connect to. If you find the connecting points, you just may find the reason for the problem.

The reason you can't remove the drain on the system by removing fuses is they probably ran power straight off the positive cluster instead of through an existing fuse.

If you still can't find the problem, measure current draw at the battery with all the fuses pulled out. If you still have any current draw, begin removing cables from the positive cluster.