Ford 1998 Windstar Owner's Manual page 211

4 mph (6 km/h). A mechanical noise may be heard as the ABS
performs a self test. This is a normal part of the self test feature.
If a malfunction is found during this check, the ABS warning
light will come on.
The anti-lock brake system light
You should always be careful when braking, even if your
vehicle has the ABS. Heavy braking on roads with loose
surfaces such as snow or gravel, or roads with severe pavement
irregularities could also cause you to lose control of your
vehicle.
If the anti-lock brake system warning light remains on or
comes on while driving, have the braking system checked
by a qualified service technician as soon as possible.
NOTE: If a fault occurs in the anti-lock system, and the brake
warning light is not lit, the anti-lock system is
disabled but normal brake function remains
operational.
Ford Motor Company has not found any negative effects of
mobile radio transmitting equipment installed on vehicles with
the ABS system providing that the radio is installed according
to the radio manufacturer's instructions. However, if you have
had a mobile radio transmitter installed and the ABS light
comes on (at any time other than immediately after turning the
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