Do you mean the horn is turning on or it's turning off? If it's turning on, why would you suspect a fuse? The circuit would be dead if the fuse blew. Either way, the clue is it changes when you turn the steering wheel. Suspect the clock spring is coming apart and the two horn wires have either broken or are touching intermittently. As the ribbon cable continues to break, the cruise control will stop working and the Air Bag warning light will turn on.