the steering wheel will most likely have to come off to solve this problem. It sounds like the return paul or spring has broken, and it was shorting the horn ring to the horn sw. At any rate this sounds like it began in the multi-function sw. and is still going on in there someplace. If you have air bags, i would let a pro deal with this, but some guys know how to disconnect the power to the air bags in order to take off the wheel, I am not one of them.