Normal Operation
WARNING: This page is about a different car, the 2005 Mercury Montego, 2005 Ford Freestyle, and 2005 Ford Five Hundred. However, it is still accessible from the selected car via links, so may be relevant.
The instrument cluster uses 2 separate strategies to operate the brake warning indicator. When the parking brake is applied, circuit 1309 (RD/YE) to the smart junction box (SJB) is grounded by the parking brake switch through circuit 1205 (BK). The SJB receives the ground signal and sends the instrument cluster a message over the communication network to illuminate the brake warning indicator. When the brake fluid level is low or a base brake system concern is detected, the anti-lock brake system (ABS) module sends a signal to the instrument cluster over the communication network to illuminate the brake system warning indicator.