Parasitic Draw Interactive Diagnostician
A parasitic draw occurs when an electrical component continues pulling current after the vehicle is turned off, draining the battery overnight. Use this step-by-step simulator to master DMM setup and learn how to identify the draining circuit by pulling fuses.
Step 1: Preparing the Vehicle for Test
Before setting up your Digital Multimeter (DMM), you must ensure all vehicle computers go to sleep. Otherwise, you'll get a false high reading, or blow the delicate fuse inside your multimeter!
Diagnostic Diagram
Vehicles must be entirely shut. If testing under the hood, bypass the latch switch using a screwdriver so the car thinks the hood is fully closed.
Professional DMM Safety Note
Never turn on the vehicle ignition, run the starter, or pull high-amperage accessories while the multimeter is connected in series in Amps mode. The sudden 100A+ draw will immediately destroy your meter's 10A internal fuse, or burn out the meter itself.