Need Some Help

The Horn, Cigarette Lighter, and dome light in my 85 monte SS isnt working... Is this a fuse?? if so i need a diagram or something so i'll know which fuse it is.

they all worked fine 2 days before now none work

do you own a testlight?? if not go buy one their cheap. turn the key to on, attach the clip on the testlight to a good ground. fuses have a post on either side at the back. probe each side of every fuse. if you get one that only lights on one post it's blown. if some don't light on either side it means there's no power going to that circuit. if all the fuses check out check the bulb. also check the 2 wires at the back of the cigarette lighter very often one breaks or falls off.
good luck!!

it has small letters next to each fuse, also the fuse box cover, located under dash left to the brake pedal should have your diagram, or i'm sure you could find it online. yes this is a fuse that controls the cig lighter, and dome light. You can pull each fuse invidivudally and inspect as a worst case scenario, but it will say right by the fuse, cig