Last year I added Classic Air vintage ac to my 1966. It utilizes the original evaporator case with an upgraded evaporator and modern compressor. We were just sitting in the car idling with the ac running when I heard a slight "pop" and the ac just quit. Doesn't matter where the settings are, and it didn't blow the inline fuse. I'm pretty sure it's electrical. My underdash harness was rebuilt by midlife, and all other wiring is new. Everything else works fine, except the horn. Any ideas?