[prairieschooner]

On our '82 the Brake Light Switch is on the Air Line Forward. It should be a Red Wire and may have a White Stripe where it comes into the Steering Column.
The Turn Signal and Emergency Flasher Switches Interrupt the Brake Signal going Aft (this is how the front emergency flashers stay on while the brake light is interrupted by the turn signal. The Brake Light Signal that was not interrupted was only at the Cruise Control in the Rear.
When I bought our '82 the Brake Lights did not function. I found the problem in the Emergency Flasher and was able to make a temporary repair while I waited for the replacement part. At that time Newell had these Replacement TRW Turn/Emergency Switches.
Good Luck, and I would like any of the old Williams DANA Cruise Control parts if you still have them, so far I have been able to keep ours going with minor repairs.