Normal Operation
WARNING: This page is about a different car, the 2006 Mercury Grand Marquis and 2006 Ford Crown Victoria. However, it is still accessible from the selected car via links, so may be relevant.
With the parking lamps on, the lighting control module (LCM) supplies a variable pulse width modulated (PWM) voltage to the electronic automatic temperature control (EATC) module (if equipped) or to the manual climate control on circuit 484 (OG/BK). The EATC has a secondary illumination source which is supplied a constant voltage from the LCM on circuit 19 (LB/RD). The manual climate control illumination is grounded through circuit 57 (BK).