Vehicle Battery Draw / Drain


A healthy car battery is the foundation of a dependable vehicle.

M&R recommends using only AC Delco batteries ( Unfortunately, a battery that is frequently going dead will significantly affect its longevity. There are many things that can affect a batteries ability to “hold” a charge. Your vehicles alternator could be defective. You could have loose battery terminal connections. Or, you could have higher than normal drain on the battery. This abnormally high drain is referred to as a “parasitic draw“.

All vehicles require power from the battery with the ignition switch in the off position. However, there is an acceptable power requirement, and an unacceptable power requirement. With older vehicles, the procedure for testing the amount of power the vehicle is demanding from the battery is pretty simple. You just place an ammeter in between your vehicle and the battery. While monitoring the draw, begin pulling fuses. Once you see the draw go away, you found your culprit circuit. Unfortunately, this method does not work with newer vehicles that have multiple, complex computer systems. In these newer vehicles the BCM( body control module ) and PCM ( power control module ) power circuits directly and can mask where the real problem is. And these vehicles will continue to require more battery power than normal, well after the ignition has been turned off. In some cases, as long as 45 minutes! This is where the expert technicians at M&R Auto Electronics shine.

We diagnose and repair these issues on a daily basis. Stop in to M&R and see why other local repair shops send their electrical issues our way. State certified techs that repair electrical issues the other guys can’t. At M&R Auto Electronics, we don’t do brakes. We don’t do tires. We don’t do windshields. We do electrical, and that’s all we do. Give us a call. 989-790-2949