How to Use a Multimeter to Detect Vehicle Electrical Leakage?
2 Answers
The method for using a multimeter to detect vehicle electrical leakage is as follows: 1. Set the multimeter to the current measurement mode; 2. Select the 20A range, then insert the red probe into the socket labeled 20A; 3. After adjusting the multimeter, turn off the engine and all electrical devices, and lock all doors; 4. Open the hood and disconnect the negative terminal of the battery; 5. Connect the red probe of the multimeter to the vehicle body and the black probe to the negative terminal of the battery, then observe the multimeter to check for any electrical leakage. A normal leakage current is below 30mA to 50mA. If the multimeter displays a value exceeding 50mA, it indicates significant electrical leakage in the vehicle.
Last time my car had a power drain that killed the battery, now I've learned to check with a multimeter. First lock the car and wait half an hour to let all electronic modules go to sleep. Open the engine bay to locate the battery and disconnect the negative terminal. Set the multimeter to the 20A current range, connect the red probe to the negative cable and the black probe to the battery terminal. The reading at this point is crucial: a normal car shouldn't exceed 0.05A, anything over 0.1A indicates a power drain. When I tested mine, it showed 0.3A and I eventually found out it was caused by incorrect wiring of the dash cam. Important note: don't open car doors during testing as the alarm activation will skew the readings. If the reading fluctuates, it might mean some module hasn't fully entered sleep mode.
