Well, i had a real bad experiance going to Ceder Key, FL. When i passes through Gainesvile, i tried to get on I-75. The moment i hit a small bump on the highway, my horn started to go off and would not stop. After trying to stop it by pressing the button (previous answer to problem), i had to pull over. And this thing is not quiet. It was hurting my ears like mad and i just pulled the power cord right off of the compressor. Problem fixed.

Anyway, when i got home, i began to look over the problem with my 12v-testing light and some electrical tape. I thought to myself, why don't i just directly wire the old horn wires to the compressor...in other words, bypassing the relay and the battery (things that the instructions said the compressor had to be hook up to for it to work). Sure enough, the horn works fine now. Just as powerful and 100 times error free. I have yet to have a single problem with it now and i don't think i ever will again (knock on wood).

So if any of you run into the same problem i did...here is probably how to fix it. Good luck.
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-Brandon at home '88 744ti 139k miles