There's a prior posting on this, indicating that the switch is available at any Radio Shack for about $2. Since it's not a factory part, it's necessary to cut the two wires of the old one and splice/solder the two wires from the replacement one. If you want to be super conservative, it's easy enough to check the operation of the mirco switch once you get at it by removing the console. Any simple electrical guage can be spliced into the leads to determine if the switch is opening/closing its circuit properly. If the switch is working correctly, then it's the solenoid that's going/gone bad.

Regardless, I have no idea if the switch alone is the best fix. When my shift release solenoid started acting up on my '93, I just went ahead and replaced the solenoid and switch assembly. The part is rediculously overpriced (about $60) but it's a straight swap with the old one (gotta remove the console to get at it).