How do you replace a headlight switch on a 2002 GMC Yukon?

To replace the headlight switch on a 2002 GMC Yukon, first disconnect the negative battery cable to ensure safety. Remove the trim panel around the dashboard to access the switch, then unscrew the mounting screws holding the switch in place. Disconnect the electrical connector from the back of the switch, replace it with the new switch, and reassemble the panel. Finally, reconnect the battery and test the new switch to ensure it operates correctly.