Edmunds Answers

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  • avatar woxof1 11/11/08 4:59 pm PST

    You 1989 vette has a blend door actuator motor located on the right side, mounted to
    the back of the heater housing. Its black box with a little arm conecting to the door
    open-close arm.

    If its working correctly it should move in and out opening and closing the door for heat
    temperature control.

    Cant buy new. Used only I found one for $250.00.

    I am trying to figure out what other models have this same motor. I cant believe its only
    on a corvette.

Answers

  • tony78 11/09/08 11:27 pm PST

    blend door not operating correctly

    possible cable linkage issue,,or vacuum motor acctuator controler issue.

  • woxof1 11/11/08 4:59 pm PST

    You 1989 vette has a blend door actuator motor located on the right side, mounted to
    the back of the heater housing. Its black box with a little arm conecting to the door
    open-close arm.

    If its working correctly it should move in and out opening and closing the door for heat
    temperature control.

    Cant buy new. Used only I found one for $250.00.

    I am trying to figure out what other models have this same motor. I cant believe its only
    on a corvette.

  • woxof1 11/23/08 3:32 pm PST

    You have no heat because the BLEND DOOR MOTOR has died. I know becasue I just orderded one USED ONLY AVBL. And it didnt fix the problem. So I need a AC/HEAT controler.


  • sprescott 10/09/09 8:27 pm PST

    Somn cars use a heater control valve that is either vacume actuated or electric and dome use a blend door to regulate the outside to cabin air.The door closes and doesn't let the hot air into the cabin. check the pass side under the hood look for vacume lines GM used to use a purple line going into the heater,check for this,if it has that make sure it gets good vacume. Also under the pass side dash panle knee bolster check for line and wires,look for obstructions around the actuators and vents.If the controls are vacume,you would notice when replacing the controls you can test the door actuators with a hand held vacume pump to see if they move with vacume applyed.this pump is about $20 from most part retailers.

    Also there are companies on the web that have DIY versions of the same source of info we use in the field they cost around $15 a year and will give you access to complete service manual info technical buletins,recalls and parts and labor.This is well worth the money and can save you countless hours of just locating a component,

  • cliff_harris1 10/27/14 4:25 am PST

    Sound like your temperature blend door is stuck in the cold position. To check that, take the blower motor control module out of the evaporator case and look into the opening. The blend door will be a rusty flat part.


    Set the HVAC controller to 90° (the highest setting) and look at the blend door. It should be in this position:

    http://www.misterpeachy.com/VettePics/B
    lend_Door_90_Position.JPG

    If it is not there are several possibilities. The blend door position is controlled by the blend door motor. There is a metal link between the door and the motor. That link might not be attached. The blend door motor with the link looks like this (from the top):


    You can test to see if the blend door motor is working by briefly removing the CTSY/CLK fuse. That will cause the HVAC control head to forget its settings. The next time you turn on the ignition it will recalibrate the blend door by moving it to the maximum heat position and the maximum cool position. It takes about 15 seconds to do the calibration. You can see all this happening through the blower control module opening.

    If the motor moves OK in one direction but not in the other direction, then the HVAC programmer might be bad. It is attached to the firewall above the gas pedal. It is quite common for the resistors associated with the blend door motor to overheat and either cause bad solder connections or for the resistors themselves to burn up. The resistors in question are shown in the lower left corner of this picture:

    http://www.misterpeachy.com/VettePics/P
    rogrammer_PC_Board.JPG

    You can see how the PC board has been discolored by the heat from the resistors. It is also possible that one of the transistors for the blend door motor has failed.

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