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Q: Something is draining my battery, both battery and alternator have been checked and are working fine.

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I am having to jumpstart my vehicle. Once it is jumpstart, it runs fine with no issues but if I leave the car sitting for about 7 hours or longer I have to jumpstart it again. The battery and alternator both have been checked and are working fine. It appears that something is draining the battery after the vehicle sits for a while. I thinking a short in maybe the battery cables or a ground problem.

My car has 10900 miles.
My car has an automatic transmission.

A: Hi. Your diagnosis is spot on! If the alter...

Hi. Your diagnosis is spot on! If the alternator and battery are good, something is causing a pretty significant drain on the battery, and this needs to be identified. 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 one from YourMechanic, can perform and electrical inspection for you, and replace/repair the failing component as needed.

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