Q: Why is my battery draining overnight?

asked by on June 13, 2016

Something is draining my battery, battery, alt., and starter are all good. I have a Toyota rav4 07. I have used a multimeter to check the amp drawal off the battery after the negative cable has been removed from the negative post. If all of the fuses are in the meter reads 0.53 (multimeter set at 10A). When I remove the ECU B fuse the multimeter goes down to 0.33. The only other difference made when a fuse is removed and the multimeter goes down to 0.01, is removing the RAD 01 fuse and the ECU B fuse. Any thoughts on what we should look at it thoughts on what is wrong?

My car has 160000 miles.
My car has an automatic transmission.

Hello. There are a few common issues on this vehicle. Before getting too far into it, I always check to see if there is any aftermarket equipment such as an aftermarket radio. Most of the time, any electronics that are added to the vehicle will cause this. If everything is original and from the factory, then the most common issue is the ignition switch. I have had a lot of issues with the ignition switches on this vehicle not turning off all of the way and causing this to occur. I usually disconnect the switch first to see if it affects the draw reading. If not, then it may be a relay that is staying on or a failure in the module. If you are going to have this repaired, consider YourMechanic, as a certified mechanic can come to your home or office to diagnose your battery draining problem.

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