1991 Ford Thunderbird horn and radio doesn't work

My radio and horn doesn't work in my 1991 ford thunder bird and I was wondering if it was a fuse problem? If it is do you know what number fuse it would be? I replaced the 10 fuses and the 15 fuses. Maybe it is a 20 fuse or a 30 fuse? I believe that the radio and horn is tied on the same fuse I just don't know which fuse because the panel that shows which fuse goes to which is gone and I am a beginner when it comes to electrical problems. If the fuses are not the problem then is there any other alternative reason that the both wouldn't work? Any advice would be much appreciated