If you're talking about the switch to turn the lights on and off:
(I scuffed my knob when I did it, so be careful and pry in a spot that will not be noticeable.)
You must first take the knob off (the knob that turns the lights and parking lights on/off. --> This is quite difficult. I had to use a really small screwdriver to get it out. It took some patience; you cannot pull it off with your hands, it need patience and prying
Then you'll notice a plastic bolt behind it, (i believe it's a 17mm)
Then you should have the bulb exposed enough to figure out the rest.
Also, I'm assuming you've already removed the assembly; if not:
The vent, parking light switch, and fog light switch are are one whole assembly; there is a screw underneath it' feel you hand under it (or ben down and look) Unscrewe that screw and you pry the assembly out bottom first. There are holding clips at the top that will prevent the top from coming out first. The first time I took it out, it was a litte stuck, so I used a screw driver and pryed from the bottom. I would not suggest doing this, but if you do be careful not to leave any marks.
Hope that helps; if you don't understand or need better instructions, let me know!
GOOD LUCK!
Sean