philip513

Hi folks - I'm a first time writer to this forum. Having a problem with my Corvette. It's a '99 with 30k miles so obviously I don't drive it very much, especially in the winter. When it sits for a couple of weeks, it runs the battery dead. I just put in a new battery and it did the same thing. Load tested the new one and it's fine.
The other night I went into the garage looking to see if anything was on and found the DIC back lighting and the heads-up display controls back lighting did not go off. (gave it 10 minutes)
I pulled fuse 25 in the intrument panel fuse/relay panel under the passenger's feet. That knocked out those lights as well as the interior lights. I could live without those panel lights but not the interior lights so I need to find the problem.
Any ideas? Is it controlled by a relay that may be sticking? Which one and how do you remove those relays?
Any assistance would be appreciated. I don't have a service manual so can't look there.
Thanks, Phil in cold Ohio
PS - my heat/cool LED panel display is also dim (has been for several months), when I get a chance I'll try the fix described in the sticky messages. Thanks for providing that.

BlackZ06

I looked in my 2001 Service Manual, but my wiring is different. Fuse 29 controls the courtesy lamps, and Fuse 25 supplies voltage for the HUD ... so someone with a 1999 Service Manual is gonna have to research for you. Sorry.

dgrant3830

Normally when those lights don't go out, a door or the trunk is still open. Assuming all are closed and if you pushed the lock on the fob, they should go out. If they did not go out within a few seconds, then I will suggest that you go to the dealer and have them connect with a Tech2 to find out what is commanding the lights on. I will suspect a door switch has broken. You might also look in the accordian tubes in the doors for chaffed wires touching the frame. Also, the '99 has a time-out feature that after 10 minutes, the lights, radio and all will shut down to prevent the battery from draining. I'll venture a guess that the BCM controls that. If its not working, then the BCM may have issues.

GUSTO14

Phil,

Pull the panel at the base of the passenger footwell and check the area for any signs of moisture. If the BCM gets any moisture in it, it can cause all sorts of extraneous electrical issues, including not timing out all of the electronics.

If you do find any signs of moisture, check the drains (located on the firewall at the back of the engine) for the heater plenum that is just above the area of the BCM. The drain on mine was blocked and water filled the plenum and overflowed through the blower motor and onto the BCM. This led to some of my center console backlights remaining on and ultimately draining the battery.

Bill Curlee has posted a lot of data in the above sticky on troubleshooting and correcting lots of electrical problems, including the one I described. I've saved a bundle of money following his tips...

Good luck and let us know what you discover... GUSTO

philip513

Gusto - checked the panel that you mentioned - absolutely no sign of moisture or corrosion in the area.
The last couple of time I checked those DIC lights stayed on only one time out of at least 9 tries.
I need to find out which of the relays is sticking (if that's the problem).
Anyone know whether Micro relay #37 might be the culprit?
It's called "Monitored (Inadvertent) Load Control"
What does that mean?!?

Thanks,
Phil