To me it appears it is a dual outlet... in my mind the diagram indicates that if the horn is connected to either 85 or 86 and the Arduino to 87a (center prong) then when the relay receives the 5 volts from the Arduino it will pull the contact closed to complete the circuit for the coil on either 85 or 86. Just when I think I see what is going on I start looking at it from a different viewpoint ... I think I will splurge a few bucks on a couple of optoisolators that way I will know for a fact that I am keeping the 5v side completely away from the 12v side so I can afford a few screw ups and maybe learn something in the process. I've been doing ok with the Arduino sketches that lead me through step-by-step like a recipe but venturing into something like this is all new to me. Thank you guys for being so patient.