Guys;

Whether the horns are wired with or without a relay (and both arragements came standard from the factory depending on model and year), the wire coming up through the steering column is grounded to sound the horns.

In the case of a non-relay setup (like: http://www.intelab.com/swem/544%20Wiring%20Diagram.jpg), one side of the horn elements is connected to (fused)power, and the other is grounded by way of the contact at the steering wheel (which, is really pretty marginal for the currents involed).

In a relay setup the relay has power, and "picking" it with the contact at the steering wheel sends power to the horn elements, which have the other side grounded.

...did you notice the (big) diff?...with a relay, the horns get switched power, without, and they get switched ground.

http://www.intelab.com/swem/544_6Vwiring.jpg actually shows both possibilities well.

For the reason above, I recommend upgrading to a relay setup. It gets full votage to the horns ...when you need 'em, you need 'em to work well!...See: http://www.intelab.com/swem/hornupgrade.htm

...hope that helps...

Cheers (and load beeps)