Accessory Signal: Description and Operation

PURPOSE
Provides a signal to the EFC control unit (ECU) that an electrical accessory has been turned on.

MONITORED CIRCUITS
^ Lighting system
^ Rear window defogger
^ HVAC fan

OPERATION
When any of the above circuits are energized, a signal is sent to the ECU. The ECU activates the fast idle control device (FICD), raising engine speed to compensate for added load from the alternator.