How do you change brake light switch for a 1966 Chevy impala?

Look under your dashboard and locate the brake pedal assy. follow it up towards the top of the dash and you will see a small bracket that holds a spring loaded switch secured with 2 jamb nuts..this switch should be 2 wired and the colors should be orange and white..(if no one has altered the wiring)...disconnect the 2 plugs..the switch can only be taken out from the rear..make a mental note of the position of the threads on the barrel of the switch..(where the REAR jamb nut is tightened to) THEN...remove the front jamb nut ..depress the brake pedal slightly and pull the switch BACKWARD to remove it from the bracket..thread the REAR jamb nut back on the threaded barrel to the position of the old one..insert the new switch thru the back of the bracket and depress the pedal slightly to thread on the front jamb nut..tighten the front jamb nut and re-install the wire plugs..(it really doesn't matter if they go back in the same position. it's a simple contact switch and will work either way..