With everything re-assembled but not installed in our wagon, I connected a small 12 volt vacuum pump to mimic engine vacuum.? The pump delivers 14 inches vacuum (roughly 1/2 Bar) enough to activate the two vacuum actuators fully in the heater manifold/distribution box.? I'll have to check how much negative pressure the old Tornado can produce - hopefully enough to make the heater distribution system functional again.? If the engine doesn't make close to 14 inches vacuum I could disconnect the original vacuum line, plug it, and use the new vacuum pump instead.
A little lubricant on the button switch system makes a difference too. You can see the little pump held in the vise.
