May be helpful, may not be....
Warning Indicator Functions
From the '93 Ford Service Manual:
(Teves Mark IV ABS)
The anti-lock brake system uses two warning indicators to alert the driver of malfunctions in the system.
The red BRAKE warning indicator will come on for only two reasons:
1. If the brake fluid level in the master cylinder reservoir falls below the level which is determined by the set point of the fluid level switch (FLS).
2. If the parking brake is applied.
The amber CHECK ANTI-LOCK BRAKE warning indicator will come on for numerous reasons. It warns the driver that the ABS has been turned off due to a symptom that exists in the system. Normal power-assisted braking remains but the wheels can lock during a panic stop while the indicator is on.
You may want to check to see if the brake lights (tail lights) come on when you apply the pedal. The manual doesn't say anything about this, but I wouldn't be surprised if this wasn't alerting you to a problem with the rear brake lights. Check the fuse under the dash to see if it has blown...