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If you only get air flow through the defroster, chances are the mode door actuator has failed. Take a look through this link:
https://www.2carpros.com/articles/air-vents-stay-in-the-defrost-position
Now the interesting thing about your vehicle is that the actuator is controlled by engine vacuum and not electric. The problem could be a vacuum leak to the actuator or something is disconnected. You will have to inspect under the dash for any indications. I will say that with the engine running, you may get lucky and hear a hissing sound or slight whistle if there is a leak, but the engine will need to be running to hear that.
If you determine that it isn't a leak and the actuator is bad, here are the directions for mode door actuator replacement. The attached pictures correlate with these directions.
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2002 Jeep Truck Liberty Sport 2WD L4-2.4L VIN 1
Mode Door Actuator Replacement
Vehicle Heating and Air Conditioning Air Door Actuator / Motor Service and Repair Procedures Mode Door Actuator Replacement
MODE DOOR ACTUATOR REPLACEMENT
REMOVAL
Panel Door Actuator
WARNING: on vehicles equipped with airbags, disable the airbag system before attempting any steering wheel, steering column, or instrument panel component diagnosis or service. Disconnect and isolate the battery negative (ground) cable, then wait two minutes for the airbag system capacitor to discharge before performing further diagnosis or service. This is the only sure way to disable the airbag system. Failure to take the proper precautions could result in an accidental airbag deployment and possible personal injury.
1. Disconnect and isolate the battery negative cable.
2. Remove the instrument panel assembly from the vehicle.
Fig.16 HVAC Door Vacuum Actuators
pic 1
3. Unplug the vacuum harness connector from the defrost door actuator.
4. Insert a trim stick or another suitable wide flat-bladed tool into the latch hole on the HVAC housing actuator mount. Gently pry the actuator latch while pulling firmly outwards on the actuator to remove the actuator from the mount.
5. Rotate and tilt the vacuum actuator as required to disengage the hole on the end of the actuator link from the hooked pin on the end of the defrost door lever.
6. Remove the defrost door vacuum actuator from the vehicle.
Floor - Defrost Door Actuator
WARNING: On vehicles equipped with airbags, disable the airbag system before attempting any steering wheel, steering column, or instrument panel component diagnosis or service. Disconnect and isolate the battery negative (ground) cable, then wait two minutes for the airbag system capacitor to discharge before performing further diagnosis or service. This is the only sure way to disable the airbag system. Failure to take the proper precautions could result in an accidental airbag deployment and possible personal injury.
1. Disconnect and isolate the battery negative cable.
2. Remove the instrument panel assembly from the vehicle.
Fig.17 HVAC Door Vacuum Actuators
pic 2
3. Unplug the vacuum harness connector from the floor door actuator.
Fig.18 Vacuum Actuator Remove/Install - Typical
pic 3
4. Insert a trim stick or another suitable wide flat-bladed tool into the latch hole on the HVAC housing actuator mount. Gently pry the actuator latch while pulling firmly outwards on the actuator to remove the actuator from the mount.
5. Rotate and tilt the vacuum actuator as required to disengage the hole on the end of the actuator link from the hooked pin on the end of the floor door lever.
6. Remove the floor door vacuum actuator from the vehicle.
INSTALLATION
Panel Door Actuator
1. Install the defrost door vacuum actuator by snapping it into place, engage the hole on the end of the actuator link with the hooked pin on the end of the panel/demist door lever.
2. Plug in the vacuum harness connector to the defrost door actuator.
3. Install the instrument panel assembly in the vehicle.
4. Connect the battery negative cable.
Floor - Defrost Door Actuator
1. Engage the hole on the end of the actuator link to the hooked pin. Install the floor-defrost door vacuum actuator to the HVAC assembly. on the end of the floor door lever.
2. Install the floor door vacuum actuator to the HVAC assembly.
3. Install the instrument panel assembly into the vehicle.
4. Connect the battery negative cable.
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Let me know if this helps. Also, often times, it is a vacuum related issue and not the actuator, so check that first.
Take care,
Joe
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Sunday, August 18th, 2019 AT 7:32 PM
