Subaru Repair: Brake light, fluid leaks, subaru legacy

Question
Ok. I have a 1996 Subaru Legacy, AWD w/ ABS. About a month after the last time I changed the brake pads, front and rear, the brake light came on. Not the one with the (!), but the one that says "brake", as though the parking brake is on. It turns on and off periodically when driving, and almost always stays on after applying the parking brake. Upon a thorough inspection, I have noticed no excessive brake wear, no difference in braking, no fluid leaks, ABS works fine, fluid level is fine, and parking brake works fine. It stops in a straight line from whatever speed with heavy braking, with no vehicle or steering wheel shuddering. Also have checked for heat from the rear tires after driving to see if parking brake is stuck, but nothing there. I have noticed that if I get on the brakes really hard the light tends to shut off.
Is there a parking brake switch that could have a loose wire? Any braking sensor that could be going out? It is really bothering my wife to drive the car with our son in case it is a safety issue.
Thanks for your help.
p.s.- thanks for the feedback on another post about the exhaust valve sticking open. Dealership told me I'd have to replace the heads, I laughed, read your post, and after 3 oil chages with engine flushes, haven't had the problem since.

Answer
The most likely cause could be either the parking park switch is shorting out or the fluid level in the master cylinder is low. But being that it most likely is, The switch there could as be going bad. The easiest one to replace would be the parking brake one. Those usually fail more due to the conditions inside of the car. Dust and dirt play a big role in that aspect of it.