Originally Posted by fuddyduddy121
I've seen some smaller bulbs in there with a twist-off base that are hard to find. Take the bulb to the GM dealer and see if he has a match.
If it'* the same diameter as a 194 but doesn't match it, it'* probably a 168. They can be identified by the color of the little ceramic insulator on the filament support; I think the 194 is white and the 168 is brown.
If it'* about half the diameter of a 194, it could be a 73 or similar, but you'll have to squint to find a number on those things. It may also be a variant that'* soldered into its plastic socket, so don't force it; assuming you actually have the bulb out of the dash now, with or without a socket attached, get it matched at the dealer or a competent auto-parts store.