Robert,
I have read some where that tapping into the A/C compressor feed causes the solenoid to cycle on and off with the compressor. The main complaint was that if you are stopped in traffic, and the A/C cycles off and on, you have to blip the throttle every A?C cycle to get the solenoid to hold.
If that's just the way things were back in the 70s, I can live with that.
But, ideally I would like activate the solenoid every time I switched the A/C on at the dash (regardless of that the compressor is doing)
thanks
Vic