Elm:
Most modern horn buttons (the column mount kind) are only rated for 5A. I have my horn wired straight through, and I cooked the button. I was unable to find a 6v relay here in town, and I refuse to pay $30 for one online.
My guess is that the horn button on your steering wheel is of a similar rating, judging by the spring cookage.
I solved the problem by installing a 60A starter button in the circuit. Horn works like a dream.
A 12v horn relay is readily available at any FLAPS and they cost between $10-$20 depending upon make and specs. I'd install one on a 12v system in a heartbeat. They aren't that difficult to install, either.
