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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?

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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