A VERY common culprit for this is a cassette-tape motor still running in the tape deck. I've seen this a number of times. You need to switch off your car, and remove the lid of the fuse-box. Note where each fuse lives, and what circuits they run - it usually says so on the lid or in your Owners' Manual. Take a photo with your phone, at least.
Connect a multi-meter to the +ve and -ve terminals of the battery, and note the figure it is making, which should be over 12 and likely under 14 Volts. Now take out the first fuse, and see if the figure drops. Repeat for all fuses - WHEN you get a drop, that is the fuse in charge of that or those circuits. It could also be a small light staying on in your trunk. Check this by setting your phone to video record, and shutting it inside the trunk - you hope that the light goes out when you close the lid, if it stays on, you have found your problem.
Multi-meters are easy to use, and cost only a few buck$, and are worth their weight in gold for problems like this!
There must be some short in the system. If you are tech savy, start at the fuse box by removing each fuse and testing current conductivity to see if there is any power looping without the fuse.
Take out and polish most ground connections.
Install a battery cut off if you think that might help.
Do a parasitic draw test. link down below to help you to do the test. Also when you check the battery "Load test" also do a cell test to see if you have a dead cell in the battery the tester for the dead cell test is about $5.00 - $10.00
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My battery keeps dying and.Ive taken it to 3 people and no one has an answer. A little background. I just bought a new battery back in April over the summer it died constantly. Got a jump took it to autozone in August they checked the alternator its perfect and just gave me a new battery. Car worked perfectly up until mid-late September. My car wouldnt start it would crank but would turn over until like the 2nd or third crank. This past week got in my car. Nothing , battery dead. Went to autozone got ny battery fully charged . Got in my car this afternoon dead. I installed a new radio over a year ago.but it cuts off when my car is off. Somebody please help. What could be draining my battery?
