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Blend Door Recalibrate?

Discussion in 'Prius c Care, Maintenance and Troubleshooting' started by Pyro da Cat, Aug 13, 2021.

  1. ChapmanF

    ChapmanF Senior Member

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    ... unable to get my browser to do anything with those s9e.github.io/imgur embeds.
     
  2. Pyro da Cat

    Pyro da Cat New Member

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    It was a video of pin test. Hot wired servo on the bench then ran continuity across the 3 pins for the pulses. 1&2, 1&3, 2&3. Checked good. I thought there was a little static/resistance in a sector of the pulses, so I took the cover off of the contacts under the drive gear and used alcohol to clean the contacts. Nice clean pulses after that. I was confident again... Briefly. Just road tested this 5 minutes ago with the dash apart. Funny thing is the blend door servo runs the blend door and changes temperature in EV, but as soon as the ICE comes on... Hot hot hot. So I'm not winning yet!!

    Is there an electronic valve on the heater core? Is the heater core it's own circuit with the coolant (meaning, if I bypass the heater core inside the cabin, does it stop circulation through the radiator)?

    Next step is remove blend door servo, road test and see if any manual position blocks the heater core. Then I'll know if the position is just incorrect.
     

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  3. Pyro da Cat

    Pyro da Cat New Member

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    I FOUND THE PROBLEM!!! Woo hoo. Still have to reset everything, but...

    The blend door itself has become disconnected from the drive gears inside the box. The servos drove the controls into positions, but since the door was full forward and no teeth engaged, it wasn't moving.

    I'm not sure how the tech said there was a circuit issue and code unless the wiring harness was ALSO bad at the SAME time...???!!

    But, reassembling today or tomorrow and am pleased to locate the issue! I'll check back with results.
     
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  4. ChapmanF

    ChapmanF Senior Member

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    Well, you did have the B1441 code, whose fortune cookie is "Air Mix Damper Control Servo Motor Circuit", and maybe the tech just looked no further than the fortune cookie, which is something I spend lots of posts here trying to talk people out of doing.

    If the tech had looked the code up in the repair manual, there would also have been:

    This sounds like good progress.
     
  5. Pyro da Cat

    Pyro da Cat New Member

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    Works like new with the blend door teeth engaged.

    I saw another part somewhere that said the box is not really designed to be fixed... I AGREE.

    We had two long screwdrivers in through the floor vents from opposing sides (like crossed swords) wiggling the door back up, and had to figure out the internal gears had an indexing tooth on them.

    Wifey and I will be applying for service positions at the dealership with our new experience.

    Hopefully someone can learn something from this post.
     
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  6. Pyro da Cat

    Pyro da Cat New Member

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    Thanks again Chapman. Your patience and wisdom have prevailed!! We did it.
     
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  7. ChapmanF

    ChapmanF Senior Member

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    I wonder what the story is for the door and gearing coming asunder in the first place.
     
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