Mike,
Is your brake switch as far forward as the slot allows? If so, it sounds like either you have the wrong PN installed or your brake pedal is not coming back far enough (how does it align with the accelerator pedal?). If the later, investigate your master cylinder and mounting. Perhaps you have a power MC & rod in a manual brakes car, or maybe a later 2 - hole MC with an adapter plate which moves it out farther. I assume somebody unplugged the switch, otherwise your brakes lights would always be on.