Field-Effect Transistor (FET) Protection
WARNING: This page is about a different car, the 2013 Ford Fiesta. However, it is still accessible from the selected car via links, so may be relevant.
A Field-Effect Transistor (FET) is a type of transistor that, when used with module software, monitors and controls current flow on module outputs. The FET protection strategy prevents module damage in the event of excessive current flow.
The BCM utilizes a FET protective circuit strategy for many of its outputs (such as a turn lamp output circuit). Output loads (current level) are monitored for excessive current (typically short circuits) and are shut down when a fault event is detected. A short circuit DTC sets when the fault event occurs.
The circuit remains off until the fault is corrected and the ignition state is cycled off and then back on, the module resets the FET protection and allows the circuit to function.