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Discussion Starter · #1 ·
I have a 96 Corvette that is driving me crazy. I seem to have an electrical drain somewhere in the car. IF it sit's for a week or so, it goes dead. It has a brand new battery, so that shouldn't be a problem.

Any one have a procedure on how I should proceed? Any ideas?

It's an LT4/6 Speed car. Factory Radio with an FM Modulated CD Changer installed prior to me owning the car.

One other thing that I don't think is related is I've lost my Vent control. It either pushes all the air to defrost, or to the floor. Can't get anything to come out of the dash vents.

Thanks in advance

Gene
 
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Discussion Starter · #2 ·
saw this on tv's two guys garage last week. disconnect ground cable from battery take a test light attach the clip to the cable. put the probe to ground. if you have a drain the light should be lit. start pulling fuses until the light goes out, then you have the curcuit that is the drain and track it from there. let us know if it works. ;)
 
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Discussion Starter · #4 ·
Measuring the current draw from the battery, using a DVM (digital voltmeter, set to measure currect) inline and then pulling fuses one-at-a-time, is the correct method. It's very likely that it is a GM radio; apparently certain GM radios are prone to failing caps that fail shorted, and that causes a current drain even when the radio & car are shut off. It can be fixed by removing the radio and R/R of the bad caps and replacing with better quality new ones. I learned this from a Bcar neighbor who knows his electronics and wiring; he also told me that this info is on the web, so you can probably search for it.

That brings me to the main reason for answering this post. That same neighbor has been chasing a similar elec drain problem on his '91 Caprice LTZ. He eventually found, by using the DVM and pulling fuses, the offending circuit. I dunno which one it was but what makes this story curious, was that he disabled the ONLY systems on that circuit so that it should draw no current --- and it still drew tens of milliamps!

So he started to trace the wires on the offending circuit. What he found, eventually, connected to the circuit and hidden behind a panel was an old LoJack rf transmitter that had a dead (shorted) battery. He removed the LoJack device and then cleaned up the wiring, and the currect drawon that circuit vanished. So that was his problem all along, but it wasn't the result of a failed GM part. Rather, it was an old hidden anti-theft device that caused all the problems.

My wife used to kill the battery in her minivan in a similar (electrical) fashion because she had an old(er) cell phone that would kick on and stay on (powered) whenever she plugged it into the 12v lighter outlet. I figured that one out after buying her a new battery and later feeling heat inside the car (by touching the cell phone).

Both of these were good stories for me to learn from and hear, and I'm likewise passing them along. HTH. - Ken
 
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Discussion Starter · #5 ·
First of all, thanks for all the good suggestions. I'll try pulling the radio fuse for now, and charging the battery, to see if that does it.

If not, I'll use the other method.

Does anyone know if there is a board like this for the Vette? If so, could you steer me to it?

Thanks
Gene
 
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Discussion Starter · #7 ·
Don't know if the 'Vette is set up the same way or not, but on our cars, there are two fuses for the radio. Make sure you pull both of them.
Good luck,
Joe
 
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Discussion Starter · #8 ·
I looked in my owners manual and saw that there were two fuses. One for keyed, and one for "hot" I guess. Pulled both of them, charged the battery, and now I'm out of town for a week. We'll see what happens when I get home.

I didn't fully understand what's wrong with the factory stereo. Can anyone expand on that a little more? Is it fixable? Should I fix it, or just go with an aftermarket radio in it?

Also, thanks for the Vette forum address.

Thanks again
Gene
 
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Discussion Starter · #9 ·
Has the engine been out lately? If so check the ground strap from the firewall to the head, that was my electrical drain problem.

Mike
 
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Discussion Starter · #10 ·
Actually, you will want to see if there is any current draw, rather than just charging the battery and seeing if it is dead later. If you battery is toast, it won't hold a charge regardless.
Just disconnect the battery cable and put a 12 volt test lite between the battery and the cable. If it lights, you still got a drain. If not, you're probably good to go. Just remember to close all the doors and disconnect the hood light!
In regards to the radio, I'm not sure exactly what happens, however it is fairly common for them to go "bad" and cause a constant drain, even tho they function correctly. That is what happened to mine, and it would pull down an Optima battery in less than a week. It can be fixed by any Delco repair shop.
Joe
 
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Discussion Starter · #11 ·
I'm not sure if they have it fixed on our year cars, but in the '80s the cigar lighter was a high failure item on GM cars. I nearly set my Celebrity on fire before I found the source of the smoke was the lighter. Of course having 9Cs1 that is not an issue.
 
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Discussion Starter · #12 ·
Ken, that same B-Body neighbor told me how to diagnose vacuum leaks to give me back control of where my heat blows out, which is what I think is most likely the problem in that 96 Vette as well, a bad or disconnected vacuum line under the dashboard.

He's a smart man.
 
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Discussion Starter · #13 ·
<BLOCKQUOTE>quote:</font><HR>Originally posted by Mike454SS:
Ken, that same B-Body neighbor ...

He's a smart man.
<HR></BLOCKQUOTE>

Yes. And like Batman, we need to keep his true identity from the unwashed masses, lest he get inundated with forum- & digest-sponges that take-take-take but do no homework on their own. - Ken, feeling like Alfred
 
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Discussion Starter · #14 ·
<BLOCKQUOTE>quote:</font><HR>Originally posted by kdrolt:
Yes. And like Batman, we need to keep his true identity from the unwashed masses, lest he get inundated with forum- & digest-sponges that take-take-take but do no homework on their own. - Ken, feeling like Alfred<HR></BLOCKQUOTE>

Yes we do, but I did remember to send him a Happy Holidays e-mail today as I did to you as well.
 
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