What does "parasitic draw" mean in automotive electrical systems?

Parasitic draw refers to the phenomenon where electrical devices continue to consume power from the vehicle’s battery even when the vehicle is turned off. This ongoing power usage can lead to a slow drain of the battery over time, potentially resulting in a dead battery if the vehicle is not used for an extended period. Devices that might contribute to this draw include alarm systems, interior lights, or any other accessories that may remain powered even when the ignition is off.

Understanding parasitic draw is crucial for diagnosing battery issues and ensuring the electrical system is functioning efficiently. If a technician discovers an abnormal parasitic draw, they can investigate further to identify the specific component causing the drain, enabling them to address any related electrical problems effectively.