GM Service Manual Online
For 1990-2009 cars only
  1. Remove the left side A-pillar defogger duct from under the instrument panel.
  2. In order to release the switch from the retainer, twist the switch counterclockwise.
  3. Important: Incorrect adjustment of the brake switch may cause the cruise control system to operate in an erratic manner.

  4. Slide the switch into the retainer until the plunger is fully depressed into the switch barrel. Ensure that the switch connector is orientated toward the one o'clock position. For additional information regarding the stoplamp switch adjustment, refer to Stop Lamp Switch Adjustment in Hydraulic Brakes.
  5. Twist the switch clockwise until you reach the travel stop. The switch will face the three o'clock position when the switch is locked.
  6. Install the left side A-pillar defogger duct under the instrument panel.