John;

...at first, I was going to tell you the switch is located in the brake plumbing, just south of the master cylinder...but then I figured out that you are looking for a new one....sorry I can't help with a new one, but...

That electrical contact function of the brake warning switch is performed by a hydraulic "shuttle" with depressions machined in, which a spring loaded plunger (the hex par which screws in from the side) drops into and closes the circuit to chassis when the shuttle is forced off center by a pressure differential...it's been a while since I've been inside one of those, but it would seem that this assembly should be compeletly rebuildable...or is your switch somehow destroyed and impossible to rebuild?

Cheers