light bulb sizes?

so far i'm fixing up the interior of my car and come to the challenge of lighting, i already have the dash and speedo changed to blue but i need to kow what size bulb goes in the rear defroster button, and then my last lighting issue is it possible to change the lght bulb in the factory switchs like the one for the foglights?

thanks, but i have already figured a way to get it to turn blue, when i tried to take the bulb out i broke it so i had an led soddered in place and it works great, although i had to cut the plastic shroud that it goes in, it looks great and so does the rest of the dash, that was the defroster switch, the foglight switch was easy to switch the bulb but let me warn anybody that tries this the switch has a lot of little parts and when you take the foglight switch apart you should have 2 springs, a ball, a piece of metal that looks like a staple and a piece of plastic with two square holes in it.