Ive been searching trying to find an answer to my dome light problem but no luck. The dome light doesn't work at all. It doesn't come on with the dome light override or the rheostat. The little spot lights do work. It has a new bulb, I've checked the fuses, I've read that the dome light has some relationship to the backup lights, which work fine. Are all the lights(dome and spotlight) supposed to come on when you open a door? Nothing comes on when I open a door, so I wouldn't think that all four plunger switches are bad. I know GM likes to ground stuff, but not exactly where in this circuit. Maybe bad ground somewhere? Any help would be appreciated, Thanks guys.

my bros blazer did this and it was the little done on off switch and brightness controll on the dash there

bad ground or a cracked wire

Test light to ground the orange wire at the domelamp. It should be always hot. If it isn't, check all your fuses. I'd start at CIG LTR. When I test fuses, I simply probe the hole at each fuse on both sides.

You're looking for a fuse that is hot on one side only, that'll be the blown one. If it's hot on both sides, it's good. If it's dead on both sides, that circuit is dead, and for this problem, ignore that fuse.