Generator "F" Field Circuit

The generator "F" terminal is connected internally to the voltage regulator and externally to the PCM. When the voltage regulator detects a charging system problem, it grounds this circuit to signal the PCM that a problem exists. The PCM monitors the generator field duty cycle signal circuit. The system voltage sense circuit receives battery positive voltage that is hot at all times through the DIM fuse in the rear fuse block. This voltage is used by the regulator as the reference for system voltage control. As generator load increases, PCM can adjust idle speed accordingly.