Fix the horn on a 92 passat (same as other VW)

The way the horn works is that the two wires in the steering wheel should be brown and they're the ground wires for the horn. The horns have 12V+ power all the time when the ignition is on but aren't grounded (so no horn) until you press the horn button. Pressing the horn button should cause two pieces of metal to contact each other and providing continuity in the ground circuit and then the horn will sound. In your case, something is installed incorrectly and the ground connection is made all the time.

Assuming your Passat is like my GTI (it probably is because the steering wheel is the same), one wire connects to a metal plate with "bumps" on it. This plate is under the horn pad button and I think it snaps on to the steering wheel. The other wire I think went through a hole in the one plate and went somewhere else but I don't recall offhand. Anyway it sounds like that when things are put together that the horn is still making ground contact as if you are pressing on the button. Something sounds like it's not seated right under the pad and contact is being made when it shouldn't be.