I have a 2002 Corvette that after sitting for a couple days in my garage appears the battery goes dead. I have replaced with brand new battery and still have issue. It will start the next day however if I don't try to start it for a couple days, everything is dead. Including the dash/console/interior lights. Acts like the battery gets mysteriously unplugged??? Nomissues with charging system according to the gauges.

I have the car at the chevy dealer now and they are going through testing all the modules. They say there are 3 left to test. They had it over the weekend and it started fine today. What is going on? Any input would be glady comsidered. Thank you!

 

I agree, one of the more common issues is one of the seat motor switches sticking on. Check them all to make sure all the motors cut off and on. Also check your vanity mirrors. If the little tab or the spring breaks, they won't turn off when closed. Best to check over the whole car in the dark to see if any lights are staying on anywhere.

 

Here is some info on battery drain diagnostics. If you can't do this find a friend who can help. Let me know if I need to clarify anything of if I can help in any way.

Suggest you remove the hood light bulb first so it does not provide a drain.

For measuring battery drain I would hook up an ammeter to the negative side of the battery by removing the negative cable and measure between the cable and the negative battery post.

When you connect the ammeter the car should draw several amps until it goes into "sleep" mode which can take several minutes. Normal sleep mode drain should be between 17-22 milliamps. You will need an ammeter that can transition from whatever the drain is down into the sleep mode. If you have a drain I suggest the following:

Once you determine you have a drain with an ammeter what I recommend first is to listen to each fuse box and see if you hear any relays operating. If not, then place your hand on each relay to see if any of them feel hot. That can be the start if you find something like that is happening.

If nothing shows up you can hear or feel then I recommend you separate the two fuse boxes from each other. This is easy and done by removing the Red cable from the engine fuse box that feeds the passenger fuse box. It is on the right rear side of the engine fuse box. There is a stud there where the large Red wire from the battery connects. Just remove the nut and disconnect the large Red wire feeding the passenger fuse box and reattach the Red battery cable. NOTE: I would recommend disconnecting the negative ammeter hookup when working on the positive side doing this.

What you will be doing is measuring the drain with an ammeter to see if disconnecting the passenger fuse box causes the drain to go away or not. By depowering the passenger fuse box you will depower the BCM which controls the sleep mode so do not expect the sleep mode to happen.

If removing the feed to the passenger fuse box you then see you have eliminated the drain then you know it is something related to those circuits. If it does not reduce the drain then you know it is related to the engine fuse box. It could be a rare case where you have some drain via both fuse boxes and we can deal with that if you think it is the case.

Once you basically know where it is then you can remove fuses and relays to see where the drain is coming from.

 

The car is at the dealership now and has been for two weeks. They say they can't duplicate the issue. Grr.. They also say they have checked all but 3 modules and so far all are ok. 2ndGrrr... I appreciate your information mostly because I suspected the dealership doesn't really know what they are doing- just going through the motions.

I will show them these threads and see if they can dig further. Thanks so much!!!

 

If they did not start with testing for battery drain you are just throwing away money having them sitting on their hands.