1992 GMC Safari horn fuse pops & radio does not work

Hello, remove the cigar lighter from the socket, see if that helps? You can use a testlite between the fuse terminals, so you don't blow all your fuses. You need to know which circuits are served by that fuse. I have a power distribution diagram for a 94, but, not a 92. For the 94 that fuse serves the radio memory--horn relay--cigar liter-- and several lamp circuits.