Mystery Battery Drain

courtesy of Bob, The Auto Answer Man

I have a Chevy with a big problem. Batteries go dead when the ignition is off. We have put three new batteries in over the last 6 months. Some said they were too small. The last one I put in was what the book called for. It is 1000amp / 800 cold cranking. I have checked for drainage with my voltmeter at several stages and don't see any drain. My son-in-law who was a mechanic for 30 years helped me check all the circuits at the fuse box and found no problem.

I took it to an Auto Electrical Specialty Shop. They charged me and said nothing is wrong. "Bring it in when the problem exists." That's a laugh How do I bring it in dead! When I go away for a couple of days I unhook the battery cable. I am at a loss. I feel it may be an intermittent short, but, don't know what to do next. It is a Caprice Classic with the a V8 and automatic
Walt H.

Here are a few things to try. One, remove the negative cable from the terminal and put a test light between the cable and the battery post. If the light glows, there is a drain. To find what circuit is causing the drain, remove one fuse at a time until the light goes away. Then, install them one at a time. When the light glows there is a drain, when the light is off, the bad circuit was removed. You may not get the light to turn off. In that case, it means that there is a drain in some other circuit that does not run through the fuse panel. First place I would look at is the starter. Starters have been known to short out at the solenoid and cause a constant drain to ground.
Good Luck!
Drive Safely!
Bob, The Auto Answer Man

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