Hooking up aftermarket horn ? on wiring

I am hooking up an aftermarket horn with compressor. What color is the wire for the horn? I think it is the blue wire. Looked in the wiring diagram I have but can't see which one it is.

 

My 1973 diagram from www.ClassicCarWiring.com shows it to be a solid purple wire.
I wud chk it with a voltmeter/test light to make sure. Hope this helps.

 

Thanks

I found it.