According to the wiring diagram, the black wire goes from the horn button to the crescent harness under the dash, out the firewall through the connection block to the relay. My understanding was that this is a ground connection and by closing the ground, the horn relay is activated, sending power to the horns (which are body grounded). But, when I press the horn button, not only are they getting power, but the entire body, too! So, unless I'm way off, either I have something wrong with the horn relay wiring, or there is a point between there and the horns that the wire is shorted against the body. If that us the case, though, why didn't it just blow a fuse? Or, I'm totally misreading the situation (as electrical work is certainly not my forte). All that I know is that with everything connected, if i press the horn and am touching the body, I get zapped!

Pic of my horn relay below.

Edit - in examining my pic and the diagram that bluebird attached, I have the red and black power wires switched, but that should not matter as they are connected and both hot anyway, But... it appears that I have the two plug in wires switched, too (black vs dark green). I'll have to verify tomorrow for sure, but is it possible that somehow by creating a ground link where the power out to the horns should be it is tripping the relay and thus feeding power back to the ground connection, setting off the horns and charging the body momentarily - essentially a short?