How to Use a Multimeter to Check for Car Battery Drain?

[McHarmony]

Method for using a multimeter to check car battery drain: 1. Rotate the multimeter's knob to the current measurement setting; 2. After selecting the appropriate range, insert the red probe into the corresponding jack; 3. After setting up the multimeter, turn off the engine and all electrical devices, then lock all doors; 4. Open the hood, disconnect the negative battery terminal, connect the multimeter's red probe to the vehicle's ground wire, and connect the black probe to the negative battery terminal. Observe the current reading displayed on the multimeter. Causes of car battery drain: 1. Short circuit or oxidation shedding of battery plates leading to self-discharge and power loss; 2. Ground faults caused by electronic components and circuits in car electrical systems, wiring harnesses, sensors, controllers, or actuators.