The fog lamps suddenly failed on my late '86 along with the dash lights ( on the radio face and a/c panel). The headlights - on a separate circuit - work fine, as do all other electrical and instrument devices. There are no blown fuses and foglamp bulbs are good. The fog lamp switch does not activate the lights.
Someone please tell me that I do not have to disassemble the dash to repair the switch wiring.

I'm not sure but on my 88 there's at least one fuze behind the info panel. I don't remember what it was for but I had to replace it when I first got this Vette. Darn if I can remember what it was for. But I never had to replace it since. My fog lamp didn't work either but the bulbs were missing. I don't remember for sure but I'm thinking the fuze was out also. It could have been that one behind there. Sorry, I wish i could be more help.