Hoping for some suggestions here... (year=1979)

I have some kind of drain killing my battery if left overnight. This has just started, maybe 2 weeks ago out of the blue. I checked the drain with a multimeter and with car off and doors closed it's pulling .115 amps (115 milliamps...I don't know what unit people prefer). This is done by diconnecting the (-) cable and running the multimeter between the (-) terminal and the cable end.

Seems that normal draw is more like .02 or so, given the clock and stuff.

So I left the meter hooked up and pulled fuses until the drain disappeared. It was the clock/courtesy light circuit.

I checked the lights, and they turn on and off as they are supposed to. I removed each bulb and no effect on the drain. The lights I checked are the overhead dome, the footwell lights, and the glove box light. I saw on some old posts that people had problems with a lamp in the storage boxes behind the seats....but I don't see any lamp there. Also I saw that people had issues with the under the hood light...again, I don't see one on my car. I see a switch that looks like it would control a light, but I don't see where the light would be. jiggling the switch has no effect on the drain.

So then I moved to the clock. I took the center console out and disonnected the power to the clock. The drain reduced to .111amps. So I don't think it's the clock, that .004 amp draw sounds about right.

Other things I checked...

I jiggled the cigarette lighter...no change.
I have a power antenna and checked/jiggled all the connections there...no change.

What could I be missing?

Side note, the courtesy lights work when I switch them on with the light switch on the dash...but they don't work when I open the doors. I don't know if I have the delayed courtesy lights...because they never go on with the door. Perhaps someone removed the module previously.

Any ideas? It's started out of nowhere, so there aren't any repairs or fixes I can go back to to check.

ANY help is warmly welcomed!

 

Find your delay and bypass it,remove the glove box.
Have you checked the spare tire light ?

 

I'll yank the glove box out and check. It's some orange box back there, right?

I saw something in the shop manual about a spare tire light, but I'm not sure where that is. I assume it's near the spare tire...but I don't see anything back there.

Incidentally, My spare tire and carrier are off the car at the moment...maybe that's doing something?

 

Yes its orange. Some have male female plugs so you can bypass and make it a non delay system.

Make sure your alarm is not engaged and due to a bad alarm horn its running the relay.

 

Eureka...I found the orange light delay. It was even slightly warm to the touch, and removing it got rid of the drain.

My interior lights never came on with the doors anyway...I always just guessed it was bad switches in the doors. Maybe it was the delay module. After removal, I still don't have lights.


The horn isn't going off....but I've never set the alarm off...I don't know if it even works. Come to think of it...the horn hasn't been working at all lately, even when driving. Could the alarm be going off and I just not know? Is the alarm related to the orange delay box?

 

The horn for the alarm is located on the drivers side on the inside of the fender by the fender vents. The road horns are in the front of the car. As far as the alarm goes I just fixed one on my friend's '80. There are five switches and a couple of relays that make it work. Here is a thread that was very helpful.

http://forums.corvetteforum.com/c3-t...ck-wiring.html

 

115mA will not drain a battery overnight. Over 24 hours that would only come to 2.5 Amp-hours. Your battery has 60-70 Ah so it would take weeks for it to drain. You either have a much higher current than you think or the battery is bad.

 

Did you put the 2 whites together at the orange relay ? This might make your int lights work.

If the alarm horn is bad,you could set the alarm without knowing it.
The alarm set is in the drivers door lock,jiggling the key back and forth can set the alarm.
Find a quiet place ,stick your head inside the car,turn the drivers outside door lock key back and forth and listen for clicking coming from the console.

 

I'm not 100% sure that the battery has had a full charge on it. I haven't had a chance to really drive the car any distance and have only had the battery on the charger long enough to move the car to the shop to check it out. I'm putting it on a long charge now and we'll see how it goes. The battery is only 13 mos old, so I'd hope that wasn't it. If I still have problems, then I think it must be battery related though.