Cause Of Brake System Warning Light Remaining On After Disengaging Parking Brake?

[The Swamp Fox]

Well, I have somewhat of a new development. The Parking Brake Light on the dash will now consistently go out after starting the car and releasing the parking brake, but resets in about 3–5 seconds and then stays on steadily no matter how many times the parking brake is set or released. Turning the car off and then back on will result in this same cycle all over again.

I've tested this without touching the actual floorboard-mounted brake pedal, and nothing changes. This leads me to believe that the light is not coming on to indicate a pressure differential in the braking system, since there would be zero pressure applied from the time the key is turned to the time that the light first presents.

Given this and the fact that the light is now going out when the parking brake is first released, I am leaning even more strongly toward a faulty brake fluid switch being the problem. Would love to hear someone else's thoughts prior to my simply throwing parts at my best guess, however. Any takers?