Charging System
WARNING: This page is about a different car, the 2003 Mercury Sable and 2003 Ford Taurus. However, it is still accessible from the selected car via links, so may be relevant.
The charging system indicator illuminates whenever the generator output is insufficient to maintain the battery state of charge or if the generator output is too high. Under a no charge condition or with the ignition ON and the engine off, the PCM provides a ground to the instrument cluster illuminating the charge system indicator. The PCM, upon receipt of a charge signal, removes the ground to the instrument cluster turning off the charge system indicator.