Changed fuse and the horn honks continuously

What year car, which fuse, and was it blown? If the horn fuse, and it was blown before, it may be that the horn relay is stuck, or there may be a problem with the horn button/wiring on the steering wheel.
More info would certainly help...

It's a 1989, and it was the 15 amp theft fuse that was blown

Hi there. This all hypatherical. Here we go. Found a small light bulb in console of mine when I brought it home , didn't think anything about it, until I got into my console for another reason ( cleaned contacts of heater unit) and there it was , an empty light socket in the info screen . Previous owner had it @ Chevy dealer to investigate low tire pressure warning light , I put the bulb in and L.T.P. Warning light came back on hmmm! Smell a rat ? He was told they corrected the problem so my point here is, could someone have removed the horn fuse because the horn ring in steering wheel is a bitch to fix? The previous owner of mine was an honest and good guy , but he was older than me , could he have gotten hoodwinked by dealer?

Had a similar problem when I bought my '94 a couple of years ago.  The fuse for the horn was missing.  I put a new fuse in and the horn honked almost constantly.  Turns out the switches in the steering wheel were all "rotted".  When I took it apart, the plastic around the switches just crumbled in my hand and was shorting out.  I bought new switches and replaced them myself.  It wasn't too terribly hard and the horn works fine now.