HVAC Blower

Has a motorized damper that upon command it lets either outdoor fresh air or indoor recirculated air to the cabin that is stuck in the "OPEN" position !!! I am suspecting a motor failure hence its stuck but thought I would put it up here to see if anyone has/had any similar situation and what was done to get it fixed and corrected ? I saw a video on YouTube about a fellow who managed to keep it "Closed" !
Now my description may sound too high tech but can't help it but to think in "HVAC TERMS" since I am a member of that Trade :bounce:
Thank you for all your input in Advance .

"The Gaspiper / Gasfitter / Refrigeration Mechanic"



Well-known member
A little lever part in the heater is broken. I have yet to ever find one that is in working order. I made a fix out of epoxy glue. Someone 3d printed the part. You can't buy just the part, just a $300 new heater.
But first, to control that door you push in the center lever of the heater controls. A red light comes on.
Took out the plunger to test it and found the following:
1- Coil in the plunger tested for continuity and multi meter Beeped ok .
2- when pressing the round knob at the controls inside, the red light comes on and tested for power out of the red wire/plug to the coil of plunger and there was power present and power off when knob turned off as well.
3- Tested for ground continuity at the plug and it is good ground .
4- There is vacuum at the brown wire that is connected to brake master cylinder all the way to the plunger with no obstructions .
5- There is no obstruction in the vacuum brown hose .
6- Moved the plunger's arm and it is moving freely .
Took the coil out of the plunger and inspected +cleaned vacuum ports .
At this point I am only guessing it is a bad plunger , the arm is ok and so is the piece attached to it and to the damper .
Has anyone gone through this ordeal and what did you do to make the recirculate /fresh air operation work?
Thank you in advance for your all help .


Engineer In Residence
You have power to the vacuum solenoid? And the vacuum lines are in good shape?

Sounds like the solenoid or actuator are bad. I will check when I get home, but I might have a spare used one. I will let you know.

Have you tried applying 12v to the actuator and using your mouth or a mitivac to test the actuator?
Yes I have power to the solenoid and vacuum lines are in good shape .
I am suspecting it is the actuator . I will apply 12 volts to it and give it a suck and see what happens .
Thank you Midwestdrifter.
On a side note ,I got the EGT and tested it before install to see if the gauge reads Zero when sensor is cold which it did , do you need actual ground to the sensor housing when testing it with a lighter to see if the reading goes up ( outside of the van with a 12 volts source) ?
Applied 12 volts to actuator and I could hear it clicking then applied vacuum to it and nothing . Took the solenoid right out and pushed the plunger arm in few times to clear the inner chambers then put everything back ,plugged power back in and when I plug in the brown vacuum hose it sounds like it is trying to pull in the arm but fails and it just keeps trying over and over yet arm stays fully extended . Measured vacuum ( Using an electronic Manometer ) at the source and found it to be the same at actuator .
At this point I am certain it is the Actuator (5133441AA).

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