[pind]

That frickin switch is on the brake pedal, believe it or not...

Lay on your back in the driver's side footwell, and with a flashlight, look up past the u-joint on the steering column. You will see a white plastic rectangle, with a wire harness clipped into it. That's the switch.

Now, the switch rarely ever screws up, that being said, it does get gummed up now and again. I am not sure what GM techs do to change them, but the last one I ran into, I merely used some aerosol contact cleaner on it, without even removing the wire harness, and it worked like a charm. Brake lights have not given me a hiccup since.

Disclaimer... I ended up having to rip the steering column off its mount bolts, and disconnect the column u-joint, to get enough room to work on the switch. Bit of a bummer.

Good luck