[vidguy]

I do have continuity between #5 and #1. On MAX A/C.
I worked late tonight and didnt have a chance to hook anything up. I will try hooking the harnesses back up tomorrow and testing the suggestions you have both made.

It sounds like you guys are correct that there is a difference in the rotary switches on 77's and 78's. That just seemed so unlikely as all of the controls and switches of those years look identical.

But after taking one apart I can see how they can put a different "switch plate" inside the rotary switch.. I guess I was unlucky in that neither of the controllers I bought in preparation for this swap are not 78's! Nor was I concerned with that.

Thank you very much,