I had to leave the original horn leads disconnected and use one of the blue/black wires (connected to the horn button) to provide the closure for the air horn relay.

I wanted to have the original horns work along with the air horns. I grounded one of the connections on each horn and then ran a wire from the second connection on the horns to the relay for the air compressor.

I wanted the original horns to function because in previous installations I found that a quick touch of the horn button simply activated the electric horns but did not allow enough time for the air compressor to spool up and sound the air horns. Seems like this set comes up at the same time as the electric horns.

Randy

I can not explain why they was no continuity to ground on the splice into the yellow wire at the horn but it still managed to provide a ground for the compression.

Splicing into the blue/black wire at the horn seems to have solved the problem.

Edit: splicing into the blue/black wire only solves the problem when I leave the original horns disconnected. Once they are reconnected the compressor activates.

I would rather be doing something simple like changing a head gasket or a rear main seal (grin)

Randy