If the horn relay is getting hot your horn button/switch is probably grounding out the same as if someone was holding it on constantly. Try disconnecting the single wire connector on the steering column (green wire I think) that should let you know if that is your problem. The horn relay acts as a bus bar as well for the electrical system if pulling the horn wire does not stop the horn relay from getting warm, connect a test light between your negative battery post and the ground wire. Then one at a time start pulling fuses until the light goes out, when it does you found the circuit that is causing the draw. Remember to pull the fuse for the dome/courtesy lights or wedge something to keep the door jamb switch compressed.