So I bought an old air products valve model 50-1555.
It is servo actuated, so I figured worst case I would steal the circuit posted on this site
, and run it with a switch or integrated pot. Best case it would run on the same voltage as the Lotus one and I could wire it with no additional wires
Well, guess what, it runs on 0-12 and will run in tandem with the heater door actuator in the heater box.
No added switch, no wires to the dash.
I found the connectors that Lotus uses for the heater control, and made a harness for it. While somewhat pricier than the cheapest available, it integrates seamlessly. i am thinking it will change the heater curve a bit but who knows if that is good or bad, most would never notice.
I can post a wiring diagram, but you can actually see it in the pic. Only trick is they use brown as 12 volt power and red as control where you might expect the reverse. The valve has power, ground and control line to what was a pot[which is discarded] and a separate power and ground source. Since we can get power and ground from the Lotus harness, why not, some nerves at first in case I smoked something, but no worries testing on the battery, works in the car
TE connectivity part numbers for the 3 pin housings:
They are a standard F crimp, I used a crimper I bought for Lucas terminals[not the commercial insulated type] and as I found out from doing this type of thing years ago, as long as the F crimp crimper is for the right gauge, a little care and they crimp fine. The totally correct crimper makes it mindless with your eyes closed job, this way you have to pay attention