[W126 Coupe] short in brake light circuit?

[Jorden1965 at aol.com]

Heres a new one for me... My 1988 SEC has developed a short.  When depressing the brake pedal, the dash gauges go dead as if the car was turned off, when releasing the brake, the gauges re-energizes and the seat belt buzzer buzzes as if the car was first started.  Ive tried isolating all the different brake lamps, but any left plugged in causes this condition.  Is is possible that there is a short to ground at the brake light switch?  Any ideas or similar experiences would be greatly appreciated.