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Home >> Ford >> 2011 >> Fiesta SES, Standard >> Repair and Diagnosis >> Accessories & Equipment >> Communication Devices >> MULTIFUNCTION Electronic Modules >> Diagnosis And Testing >> Body Control Module (BCM) >> Principles of Operation >> Field-Effect Transistor (FET) Protection

Field-Effect Transistor (FET) Protection

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.