ABS Warning Indicator
WARNING: This page is about a different car, the 2004 Ford Pickup, 2004 Ford F550 Super Duty, 2004 Ford F450 Super Duty, 2004 Ford Excursion, and 2004 Ford Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.
The yellow brake warning indicator is used to indicate a concern or deactivation of the ABS. It illuminates when triggered by the ABS control module and stays illuminated as long as the concern remains in the system.