New battery draws down overnight. Unable to find the problem. I have checked all the obvious things. Has been in the shop for 2 wks. They are unable to find the problem. Any ideas? Don't know where else to look. Car throws no OBD codes. Can the ECM do this and if so, how do I check it. Dash? Any help greatly appreciated.

Had similiar problem, mirror lamp over visor left on, maybe you'll get lucky also!

Alternator can short and have a constant draw on the battery being energized. Ive had that happen.

put a test light between the pos. cable and the pos. post on the battery. with every thing off, if test light lights up, there is a draw. if not the battery is not holding a charge

Will look at the sunvisor light, had the alternator checked and is ok, and already checked the the draw via the battery cable. There is definitely a draw. Still searching..... Thanks for the replies so far.

silly question here, does your dash cluster work ok? That is a big draw on your power if it has any issues.

It seems to......but that is the next thing they are going to check.

Mine did the same thing and it was the relay for the headlight motor.

Go to Autozone, they will check your alt while on car at no charge, I strongly suggest NAPA or another quility house for parts, Autozone gave me 3 brake boosters in a row all bad....when ever I need alt, water pump, starter etc its got to be a good quality unit. Big box stores are good for oil,polishes,rags, lamps etc........ the few extra $$ are cheap ins.... the part will give many yrs of good service........voice of experience from 40 yrs of Corvette ownership. (Autozone/booster experience was when I bumped my head)

Thanks, will relay these things to the mechanics.

my door lock switch went bad and sat and clicked every few seconds throughout the night and killed my battery, a had to replace the whole module.