Your A/C thermostat is nothing like mine, I thought you had the wrong part when you said you had 3 wires but I checked on slhondaparts.com to see what part it was and noticed that there are 2 different A/C thermostat, on the 92 it's the part #33 and on the 94 it's part #32 on these diagrams:
http://www.slhondaparts.com/browse.a...ViewParts=true
http://www.slhondaparts.com/browse.a...ViewParts=true
Anybody has a 94+ helm that could scan the wiring diagrams for that area? So we can find out what's this 3rd wire for.
As for the mode control motor, yes you can keep the USDM motor, that's what I did. I didn't have time to check in my Helm yesterday, I'll try to check tonight.