Now, what would you need a cab light for? There are only about 5 controls in the whole truck, and you can reach both sides without stretching!
Seriously, there's a "hidden" 3-pole switch under the dash in about the middle which turns on a "courtesy light" over the ignition switch when switched one way, or the instrument lights when switched the other. I reckon you could jumper one pole to the other, so that both came on always. . .
My firetruck has a search light you can point into the truck - now THAT'S a cab light!
-Michael
