The stop light switch is the device that activates the brake lights of your GMC Envoy whenever you step on the brake pedal. If the switch fails, your brake lights may stay on all the time or not come on at all, depending on the position at which the stop light switch began to malfunction. Thankfully, replacing the switch is very simple and does not take more than half an hour.
Open the driver side door and locate the stop light switch on the brake pedal, just underneath the dash. Use a flat-head screwdriver to pry off the left sound insulator and the push rod retainer from the brake pedal pin.
Remove the screw securing the stop lamp switch with a Phillips-head screwdriver.
Remove the stop lamp switch wiring connector by pulling it off the switch, and remove the stop light switch.
