Howdy fellas, I got kind of a weird problem going on with the '94. The ABS and Parking Brake warning lights will come on at random while driving. The brakes themselves operate fine, no problems are evident. Yet the lights are coming on.
This leads me to believe that it is a sensor problem. Either a WSS or maybe the Brake "on" switch?

Any ideas?

 

Maybe begin with a check of the under hood brake master cylinder reservoir fluid level & condition of the brake fluid.

There have been posts about the brake master cylinder level float sticking & causing mischief, or it turning the brake warning light on if the linings & pads are worn out, as that'll cause the master cylinder fluid level to naturally drop, as they wear. Of course if the wheel cylinders, lines, or fittings are weeping fluid, that'll also cause the reservoir level to drop & the float to turn the dash brake warning light on.

We should be flushing the system at least every 3 years with Motorcraft PM-1 DOT-3 brake fluid, to keep the absorbed water level in the fluid in check, to prevent corrosion of internal hydraulic brake parts & the wheel cylinder pistions from sticking & the fluid in there from boiling during hard braking & causing a soft, or to the floor pedal. EDIT: Where are you on the boiling point curve???? http://www.aa1car.com/library/bfluid.htm

Some thoughts for consideration, let us know how your trouble shoot goes.