Question about Jeep Liberty

2 Answers

2003 Jeep liberty 3.7L AC or heat will not blow out of center duct only through defrost. Is this system controlled by vac at selector switch? What are possiblities?

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  • squindojr Jul 29, 2010

    need to know where to test for vac motors on 2003 jeep liberty for the HVAC? The air only blows through the defrost .

  • squindojr Aug 04, 2010

    yes --thank you

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It sounds like you have a broken door in the hvac box. Check the mode doors and actuator operation first.
1)Vacuum line and Connectors.
2)Panel door Actuator.
3)Vacuum line and connectors.
4)Floor/defrost door actuator.
5)HVAC Housing.
Some operation info for testing:
NOTE: This vehicle uses vacuum to operate only the recirculation door. All other controls are cable operated.
When vacuum is supplied by the A/C-heater control to the recirculation door actuator, the recirculation door moves to the RECIRC position. The actuator is spring loaded so the door moves to the Outside-air position when there is no vacuum supplied. The operation of the door can be viewed by removing the blower motor and looking up into the HVAC unit inlet.
Normally, vacuum is supplied to the actuator by placing the recirculation control knob in the RECIRC position. The Mode and the recirculation control are mechanically interlocked so the recirculation control cannot be placed in the RECIRC position if the mode control is at/or between the mix and defrost positions. Vacuum is supplied to the actuator only when recirculation control is at the RECIRC position. If the recirculation control is between the Outside-air position and RECIRC position the system will still be in the Outside-air position. If the recirculation control is in the RECIRC position and the mode control is moved from the floor to the defrost positions, the recirculation control will move from the RECIRC position, to the Outside-air position beginning at the mix position. This is to help prevent window fogging
 The doors are located in the box halves(upper and lower).
 Yes, check vac and lines. If you have a hand held vac pump you can apply vac to see if they work and hold vac, as they leak sometimes.
You can also disconnect the actuators and try to operate the doors to see if they are broken or stripped out.
The hvac box calls for dash removal. It can be a daunting task for the do-it-yourselfer.
 The blower motor resistor is mounted to the rear side of the HVAC housing on the passenger side of the vehicle.
Thanks. Keep updated for any more query. You can rate this solution and show your appreciation.

Posted on Jul 29, 2010

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There are vacuum lines that control some of it. There are 2 halves to the hvac box and requires the whole dash be removed to replace. If you have handheld pump you can check the vac to see if its working or if it's leaking at all, you can remove the actuators to see if the doors are working or are stripped. You may want to consider professional repair for this job.
Thank you,
Lee

Posted on Jul 29, 2010

  • Lee A.
    Lee A. Aug 04, 2010

    if you found my information helpful please consider accepting/rating my solution accordingly.
    Thank you,
    Lee


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1997 Ford Taurus front defrost not working


. Air won't blow out of the floor or center vents just defrost ? Do you have manual or automatic climate control ?
Air Flow Control
Air flow control is accomplished in the following manner:
  • Primary control is through the function selector knob mounted on the A/C-heater function selector switch, which is part of the integrated control panel.
  • The function selector knob has the following positions: OFF, MAX A/C, A/C, PANEL, PANEL/FLOOR, FLOOR, FLOOR/DEFROST and DEFROST. The A/C-heater function selector switch combines a vacuum selector valve with an internal electrical switch.
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vacuum control motor-i4bq0ig33y1522pr2d2rrkk3-2-0.gif

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SECTION 412-01: Air Distribution and Filtering 2000 Expedition/Navigator Workshop Manual DESCRIPTION AND OPERATION Procedure revision date: 06/17/1999 Air Distribution There are two sources of air available to the air distribution system:
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expedition air flow hvac system-xvcmtr1jbqa4kfrdszeh0lpe-3-0.gif Item Part Number Description 1 18A318 Vacuum control motor - panel/defrost door 2 18A478 Panel/defrost door (full vacuum position) 3 - Defrost airflow 4 - Side window demister airflow 5 18B545 Temperature blend door (full heat position) 6 19860 A/C evaporator core 7 19A813 Air inlet duct door (full vacuum position) 8 - Outside air inlet 9 18A318 Vacuum control motor - air inlet duct door 10 - Recirculated air inlet 11 19805 Blower motor 12 - Vacuum to emission control 13 - Vacuum from the engine intake manifold 14 19A563 A/C vacuum check valve 15 19A566 A/C vacuum reservoir tank and bracket 16 19B888 A/C-heater function selector switch 17 18476 Heater core 18 18A559 Floor/panel door (full vacuum position) 19 - Floor airflow 20 18A318 Vacuum control motor - floor/panel door 21 - Panel vent airflow
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