FIXED IT (sort of)
After looking at things a second time, I determined that my problem was a lack of power. (What I thought was a power lead, was just the 12v for the switch illumination.)
The mirrors are supposed to receive power from a delay relay that continues power to the mirrors (& radio) once the key is turned off, until the door is opened. That was not happening. The mirrors were dead alltogether, and the radio would not stay on once the key was turned off. The power windows were working 100% as advertised though. They would work with the key off until the door was opened.
So what I did was put a temporary jumper wire from the 12v lead for the power windows switch and to the power terminal for the mirrors switch. The mirrors are now working as they should be.
I figure I have a broken wire some place. Every fuse in the truck was good. I accounted for every relay on the under dash fuse panel or under hood power central. The delay relay seems to be functioning based on correct power being supplied to the power windows. I don't see anything else on the wiring diagram that could explain anything other than a broken wire.
So for now, the mirrors are working again. But now that camping season is over and the camper is ready for storage, I probably won't have to move the mirrors again until spring.