Hey everyone. I am working on a 1982 Chevrolet Corvette V8-350 5.7L that has a drain on the battery when turned off. It will pull about 3-4 amps for about 10 seconds before going back to normal. It sets at normal levels for about 30 seconds before the amps spike up again.

The only circuit I have been able to disconnect that stops the pulling is from the clock courtesy fuse. I have pulled out the dash and removed every plug including the courtesy lamp delay timer. I even went so far as to unplug the ECM. It still pulls the 3-4 amps for 10 seconds every 30. If anyone run into a similar situation I could use any input. Thanks in advanced

 

The clock uses a timer and a small motor to wind the spring.

 

Remove your negative battery cable. Set your meter to read amps....not milliamps so you don't damage your meter. Hook the meter between the cable and the battery. See how many amps you're drawing. Now start isolating circuits from the electrical system until the drain stops. Pull fuses, disconnect wires. That should isolate the drain.

 

Pull the fuse for the clock and see if it goes away
M

 

Well I do not know if this is similar or not but I had 2 battery drains on my 1977 Corvette. The first one I found was a bad Courtisy light Switch on the Hood Light and the second was the Horn was stuck after the plastic inside it broke off. Even though I disconnected both horns it would still kill my battery in about 2 to 3 days. After I removed the horn switch assembly and disconnected one of the leads to the hood switch all my problems went away. I just happen to have 2 drains on the battery.

The hood light drain was easy to find because the light would flicker on and off all the time. The horn blew me and others away one day. I was sitting a stop light when the switch broke and the darn thing was blowing the horn at a red light than had to have one hand on the horn all the time so it would not irritate others. Kept blowing the horn at others till I pulled over and disconnected both horns. Even though they were disconnected my battery would drain.


Took me another week to figure out that even though the horns were not connected it would still drain the battery. I bought a light prob/wand to find it out and used the old method of checking each fuse. Horn fuse was still drawing power even though the horns were not connected.

I have the parts in a basket and getting ready to order the replacement parts once I figure out what else is wrong with my 1977 that sat for many years.

 

If your interior lights DO NOT dim automatically (they should on an '82, I believe) once you turn the ignition OFF, chances are the light dimming module is defective and that it is the culprit in your battery drain problem. Set up your ammeter to look for the drain again. Then, pull the fuse for the interior lights. If the drain goes away, it's a good bet that the dimmer module is the problem.

 

Ok, lets cover all the bases mentioned above. First of all, I am using a 12 amp meter in series with the battery that has a range of 1 milliamp to 12 amps. That is how I know it is draining at a rate on 3.5 amps for 10 seconds then drops to 1 milliamp for 25 seconds then consistently repeats this pattern. The next thing is I have pulled the clock/ctsy fuse and that does stop the drain. However when checking the electrical diagrams this fuse powers a bunch of stuff. Next, since it was a consistent timed drain, I figured it was the courtesy dimmer module. It dimmed as it was suppose to but I unplugged it anyway and still had the issue. Here's the next interesting tidbit. I also figured it may be the clock since it is a timed issue, but, I can not find the clock anywhere making me think the gauge panel has been replaced with a different model gauge panel. Where is the clock suppose to be located on an 82? I have pulled the hood light out and have the same issue. I haven't checked the horn circuit but I will now since it has been an issue for other people but I really can't see as either of these last 2 issues could be the culprit simply because of the consistent time issue of the drain. I will say of all the issues I have to deal with on a daily basis, I hate electrical gremlins the most. Hope someone has an answer for me! lol

 

Depending on what radio you have (original equipt.) the clock could be part of the radio & the instrument cluster would have a trans. temp. gauge. Additionally to the poster that referenced the horn issue, pulling the lead off the horn will stop the horn but there will still be juice @ the horn relay, hence the drain. Good luck, electrical issues generally suck.
Peace,,, moosie

 

Particularly, intermittant electrical problems. On thing's for sure: when you find the fault, the symptoms will make perfectly logical sense.

 

If the amp draw is timed perfectly, my guess is it's the factory alarm or an aftermarket alarm.

The alarm circuit in my '75 worked but the horn was bad. The horn caused a current drain each time it energized but didn't make a sound.
The alarm horn on the '75 is located in a rear wheel well and has nothing to do with the normal horns up front...not sure what the setup is like on an '82.