EUREKA!!!!!
Finally solved this problem. As suspected it was a bad ground connection. Not with the horns or directly related parts. It was the braided ground strap connection! Decided to go all the way back to square one and check the connections there after removing the horns and successfully testing them on the bench. They worked well, just as before the initial install.
So...the lesson relearned, “It’s the GROUNDS STUPID!”
