You may be dealing with the problem I had initially when I installed some missing pieces in my steering wheel horn assembly on my 66 pu. If you tighten the 3 attaching screws for the inner cup of the horn button (attaching the plastic sleeves), it pulls the inner cup down and flattens out the spring behind it, making continual contact with the horn spring, making the horn sound all the time.
You need to back off on those 3 screws enough to allow the inner cup to have some back and forth play.
Bert
