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Q: Battery drains overnight - 1990 Cadillac Allante

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My car has gone 154,000 miles. It's been running fine with no major problems. However, there is the issue with the battery drain. The car battery is new. I checked the alternator as well and it works correctly. The battery still gets drained after the car sat for the night. All the lights turn off when I turn the car off. There is nothing obvious that could be draining the battery. Do you have any idea what could casue this?

A: This problem can be diagnosed by connecting...

This problem can be diagnosed by connecting an ammeter to the positive (red) battery cable, observe the current drain (likely less than 1 amp). Then, one at a time, remove each fuse, check to see if the current drain has dropped to near 0, then reinsert the fuse. This process should identify the faulty circuit in most cases. A professional mechanic, like YourMechanic, can perform this procedure for you, and replace/repair the failing component.

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