With the battery disconnected, pull the switch knob out. Reach behind the dash and press the release button on the headlight switch housing. It is a spring-loaded button, about 1/4" (6,5mm) diameter. Keep pulling the switch knob while the button is pushed; the knob and shaft will come out of the switch. Then, unscrew the switch attaching nut. It is a slotted, round nut that is visible after the switch shaft and knob have been removed.
Pull the knob straight off the switch.
Then remove the retaining nut that holds the switch to the dash panel.
Disconnect the power wire from the terminal at the rear of the lighter (round, spring terminal). Disconnect the lamp from the outer, rear housing(spring clip).
Hold the front of the lighter so it doesn't rotate and unscrew the outer housing from behind the dash.
1968 Pontiac GTO
1983 Pontiac Bonneville (G) wagon
2008 Pontiac G8 base