Why does my engine temp fan run constantly while the car in on but turn off when the car is off?

If your engine temperature fan runs constantly while the car is on but turns off when the car is off, it may be due to a malfunctioning temperature sensor or a faulty thermostat that is causing the fan to run continuously to prevent overheating. Additionally, it could be a sign of a problem with the engine control unit (ECU) or wiring issues that cause the fan to operate incorrectly. When the car is off, the fan stops because the engine and its associated systems, including the electrical controls, are no longer active. It’s advisable to have the system checked by a mechanic to diagnose the specific issue.