I have a box of “bad” actuators.
Some that are locked up, some that is open circuit, a couple melted (interior fire), one that is melted (actuator shorted out), a couple that are corroded beyond reuse, a dozen I’m not sure what is wrong with other than they don't work, and a few I have attempted to repair.
I can usually repair most things electronic/electric – but have had zero luck on these actuators (which have been out of production for 20+ years).
Basically, it works as a form of electrical tug-of-war.
The resistance from the Ambient Temp Sensor (bolted to front of evaporator case – White Circle below) combined and the In-Car Temp Sensor (Red circle – the one with the 2 flex- hoses attached to it) and also combined with the resistance from the A/C Control Head - the feed from those 3 items then goes into the actuator.
If the voltage is high (from low resistance of the 3 combined resistors) then the electric motor spins in one direction, slowly.
If the voltage is low (from high resistance of the 3 combined resistors) then the electric motor spins the other direction.
If you can picture, in your mind two electromagnets tugging on an iron pendulum. One pulling it one way for a bit, the other the other direction a bit until it finally evens out (at your selected temperature).
In this case, I’m glad you were able to get it fixed.
I’ve spent years working on these (on and off) and have yet to get one to work for me.
Every time I go to a pull-a-part, I always grab the one in the car – so I have 3 or 4 of them to test (that is, if I can find them, to test them), but so far, I hadn’t found a confirmed “good” actuator from a pull-a-part, yet. I’m also not hopeful the untested ones I have work, either.
Below is PDF files of the SATA wiring – to show what I described (above).
BudW