so it's been about 3 times since the battery has drained itslef overnight.  the shop that did the complete overhaul on the car thought that maybe the speakers/amp connection was draining the battery, so they unplugged that...the next day, battery was dead.  it's back in the shop now, and they say there's a draw on the battery from the wiper motor...which is broken anyway, the wiper door is stuck open.  they're gonna check and make sure that's the only thing.

anyway...my question is...well, the car's been sitting in the shop for 3 months.  before the engine blew, back in the spring...the wiper motor was still broken, but the battery never drained itself...and I left the speakers/amp hooked up all the time, and the battery never went dead.  could it be something the shop did?  if they need to pay for the repair, I want to know.

It could be any number of things, maybe related to their work, maybe not. They need to do some basic electrical diagnosis to find the problem instead of making excuses that's it's not their fault.

They could have hooked something up wrong or grounded a wire causing a steady electrical drain. It could be a light switch gone bad that has nothing to do with the shop's work. It could be a diode in the alternator gone bad. Lots of possibilities.

If the battery is draining overnight, that's a pretty significant electrical draw and I would think not too difficult to determine what circuit it's on.

That damn Murphy guy is at it, again!

I'd have to agree with Gunslinger, in that it would take a pretty large draw to kill a good batt. overnight, and therefore should be pretty easy to isolate. Maybe the guys at the shop hooked up something that wasn't hooked up before, and now the drain is there.
It could be the "limit' switch for the wiper door. It keeps the wipers from operating until the door is open(or, at least it's supposed to work that way!), and hold the door open until the wipers are in the "parked" position.

Then again, it could very well be something totally unrelated, such as the alt. You never really know when something's gonna take a dump.

Give the guys a day or so to see what they come up with. Then get yourself a disconnect switch, just in case. Fire is not a 'Vette's friend! A lot of classic 'Vettes have been lost due to a short in the 'lectrical system. Don't let yours be one of them.

I have seen at least one case of an aftermarket ign. system killing a batt. pretty quick, because it wasn't wired up correctly. I think it was an "MSD" system but I really don't remember.

I don't have a battery disconnect but every time I put the car away I always disconnect the ground cable. I run a gel battery, I don't drive during the winter, it might be weeks during the summer,disconnected when not in use the battery is always hot and ready to go when I need it, it seems that corvette's have battery problems even when nothing is wrong.    anips38587.8802662037