Brake Light On - 95 Windstar

What conditions drive the brake light other than low brake fluid and emergency brake "ON" or is this all? My brake light has been on intermittently when going down a steep hill, so this tells me it's fluid level. The ABS light was coming on intermittently as well. The master cylinder level was at the maximum level, but I topped it up further and the light went off. The ABS light is off as well. I noticed two electrical connections at the master cylinder. One is at the bottom center which looks like it might be the low level sensor?? At the front bottom is another switch that looks like possibly a pressure switch/transducer? Any help would be appreciated!!

Thanks!!

A pressure imbalance between the 2 sides of the system will cause the Brake light to come on.

Note that the sensor on the front bottom of the master cylinder is part of the cruise control system.