This is remarkable. If it were my car at this point I'd seriously consider trying to convert at least the heater valve to manual. I have seen this done on a 77 300D which had the same "evil servo" system as your vehicle and it can be done.

The owner of that car had placed the gadget he installed up under the dash where you had to fish around for it by feel. But with a bit of thought I'm sure something could be fabricated to make the lever more accessible. Thing is it's something you'd only need to open one or two days per year. This is Phoenix after all and a heater is the single most useless piece of equipment wasting space in a car.

As for the recirculation flap. Can't comment on that one, sorry. Must say you've done an incredible job so far.

- Peter.

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2021 Chevrolet Spark
Formerly...
2000 GMC Sonoma
1981 240D 4spd stick. 347000 miles. Deceased Feb 14 2021
2002 Kia Rio. Worst crap on four wheels
1981 240D 4spd stick. 389000 miles.
1984 123 200
1979 116 280S
1972 Cadillac Sedan DeVille
1971 108 280S