I've got a '90 Vanagon that has intermittent brake light problems, where the lights sometimes stay on. I took the switch apart, and cleaned it, but the lights sometimes still stick on. There is a rubber vacuum line going to it, in addition to the electrical hookup.
I don't know what the vacuum line is for, and interestigly, if I disconnect the switch and operate it manually, the lights won't work unless I also depress the brake pedal. Is there something else besides the switch that controls the brake lights??
That's kinda funny. When I originally read your post I envisioned the two switches on the master cylinder and so your post made no sense to me and so I didn't respond.
My Rabbit has the brake switch on the brake pedal, and not on the master cylinder. In fact, in all of the cars I've evr had, the brake switch is on the pedal. You can probably figure out that the cars I drive are of the "vintage" variety.