Heat only works @90*

Discussion in 'Interior' started by Spaceman Spiff, Sep 9, 2018.

  1. Spaceman Spiff

    Spaceman Spiff TYF Newbie

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    Eric
    05 Tahoe, auto climate control.
    Just purchased in late July.
    Today temps went down to mid 50’s, so I figured it would be a good time to test the heat out.
    Well, it only blows hot/warm at the max, 90* setting. Even if I put it to 89*, it starts to blow cool air.
    Set both sides to the same temp, or on different settings, it’s the same thing.
    Is this common? I would say heater core flush, but why would it only work on max temp?
    A/c blows cold, no problems there.
     
  2. Doubeleive

    Doubeleive Elite Member Supporting Member

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    either you need the blend door actuators recalibrated, or the actuators are bad, or the control module is bad, pretty unlikely to be anything with the heater core at all unless your truck has no thermostat and runs cold all the time
     
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  3. swathdiver

    swathdiver Full Access Member

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    What He said! ^^^^
     
  4. V30Crewcab

    V30Crewcab TYF Newbie

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    actually my dads 2000 truck didn't' have heat last year, ended up flushing the heater core with a garden hose and suddenly it had heat again. but it didn't' have any no matter how hot you set it, so probably not your issue.
     
  5. MrBalll

    MrBalll Full Access Member

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    Found out a few days I have this issue also. Is there an easy way to tell which needs to be fixed as far as an actuator or the control module?
     
  6. Doubeleive

    Doubeleive Elite Member Supporting Member

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    you can pull the cover off under the glove box and visually watch the actuators to see if they rotate when making adjustments on the controller, they have a round slotted/hole, watch the hole to see if the mechanism moves or not.
    some have a plastic slot and some are metal not sure which anymore on the nbs but they all operate the same, but this what you want to watch move
    **also different actuators do different things some direct air up/down, some divide the hot/cold, so if you don't see one move then just move the controller to up/down etc. if it doesn't move for any setting then it may be bad.

    slot.jpg
     
    Last edited: Oct 1, 2018
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