2003 International 9400I with no heat in the cab

Discussion in 'Trucks [ Eighteen Wheelers ]' started by bulldozerbert, Sep 16, 2009.

  1. bulldozerbert

    bulldozerbert Medium Load Member

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    Just wondering how the heat selector sends signal to the valve ( or whatever gizmo changes heat to cool) works in an International 9400.

    I had no heat in the cab today (the taps are all on under the hood). So I took the dash apart at the fan speed/ heat selection. There are no wires or cables on the heat switch. So how does it actually change the heat setting?

    I tried the bunk heater and it works perfect, so somewhere something is not opening up.

    Thanks for any input.
     
  2. Heavyd

    Heavyd Road Train Member

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    The heater box under the passenger seat will have the hot/cold selector flap. These are common for warping over the course of time and getting jammed. The driver controls send and electrical signal to a stepper motor under the seat that moves the flapper. Diagnostics are pretty simple. remove passenger seat. remove heater cover. inspect flapper, operate controls, see what happens. If the flapper is warped you will be able to see that. When operating the controls the motor should struggle to move it. If nothing happens, then either the control head or the motor is dead.
     
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  3. bulldozerbert

    bulldozerbert Medium Load Member

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    Thanks for the info.
     
  4. bulldozerbert

    bulldozerbert Medium Load Member

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    had the mechanic look into this. said the flapper was the trouble.

    Good diagnostics. What is your fee??:biggrin_25525:
     
  5. FunkRider

    FunkRider Light Load Member

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    FYI the "hot/cold selector flap" is generally called a blend door and the stepper motor that controls it is called a blend door motor.
     
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  6. bulldozerbert

    bulldozerbert Medium Load Member

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    I thank you for the proper wording.:biggrin_25514:

    I just drive the truck, and you must obviously work on them. :biggrin_25525:

    I at least did not call them "thing-a-ma-jiggy" and "what-ch-a-ma call it"
     
  7. FunkRider

    FunkRider Light Load Member

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    No, I'm not a mechanic...but I did stay at a holiday Inn-Express last night! lol I'm just a driver too but I used to be a 4 wheeler mechanic years ago and I've spent some time working behind the parts counter at a Ford dealership. Truck cabs are getting closer and closer to being exactly like 4 wheelers.
     
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