Circuit Operation
WARNING: This page is about a different car, the 2005 Dodge Stratus and 2005 Chrysler Sebring. However, it is still accessible from the selected car via links, so may be relevant.
When the fog light switch is turned on while the front-ECU is illuminating the taillights or headlights (low-beam), the ETACS-ECU sends a 'light on" signal to the front-ECU, causing the front-ECU to illuminate the fog lights.