No air to vents

  • 3.4L
  • 6 CYL
  • 2WD
  • 120,000 MILES
Header core replaced when it started.
Do you
have the same problem?
Tuesday, November 10th, 2020 AT 7:51 AM

1 Reply


The direct of airflow in the truck is determined by what is called a Mode Door. Based on your description, it sounds like that may be bad. However, before we jump into replacing it, I need to know if you are able to change the air flow between floor and defrost.

On most vehicles, the mode door actuator is electric. On this vehicle, it is controlled by engine vacuum. So, a vacuum leak could be causing it not to react. If you are unable to change the airflow direction at all, then first check for disconnected vacuum hoses under the dash, under the hood, check for dried can cracked hoses, and so on. Note, oftentimes with the engine running, you may hear a hissing sound if there is a leak.

If the only issue is related to the vent airflow, there is a specific vacuum motor that may be bad. I will provide the directions for replacing it. However, make sure it isn't a leak before you get the new part.

Here are the directions. The attached pic correlates with the directions. Note: This component is under the dash/approximate center.
Panel-Defrost Door Actuator
1. Disconnect and isolate the battery negative cable.
2. Remove the instrument panel assembly from the vehicle. Refer to Instrument Panel Assembly in the Removal and Installation Instrument Panel Systems for the procedures.

Panel-Defrost Door Actuator
imageOpen In New TabZoom/Print

3. Unplug the vacuum harness connector from the panel-defrost door actuator.
4. Remove the two screws that secure the panel-defrost door actuator to the heater-A/C housing.
5. Rotate the panel-defrost door actuator clockwise about one-quarter turn to disengage the hooked end of the actuator link from the hole on the end of the panel-defrost door lever.
6. Remove the panel-defrost door actuator from the heater-A/C housing.
7. Reverse the removal procedures to install. Tighten the panel-defrost door actuator mounting screws to 2.2 Nm (20 in. Lbs.).


I hope this helps. Let me know what you find or if you have other questions.

Take care,
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Tuesday, November 10th, 2020 AT 12:12 PM

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