So, that would rule out switches/pods, clockspring, and fuses.
Brake pedal switch appears to be working, but you can verify with the Auto Trans shift interlock (press brake to get out of Park), which typically uses the same contacts, not the same contacts as the brake lamps.
Leaves pretty much nothing else but the servo itself and master cylinder brake pressure switch (which you can and should jumper, just to rule it out. It sends 12v to the servo, meaning brake not pressed, but if it's leaking, that 12v may only be 7 or 9 and things are getting hot. That's why all those Fords ignite, finding 12v going through brake fluid to ground, smolder city).
I'd give the whole she-bang a good visual inspection. Verify the servo linkage isn't binding, give it a squirt of lube, maybe dismount it and let it run down in the cable.
I'm **** enough to jackstand it and have someone (that I've thoroughly briefed) operate the cruise while I watch it from the side of the enginebay. If you do this and see it move a tad each button press, I'd figure the servo went south on ya.