Cannot change air from floor to vent or defrost why?

You need to check for voltage to the actuator. Did you do that?

Roy

Okay, does the motor work out of the car and hooked to the car harness?

Roy

Okay, then the issue is in the case. The door is not moving.

Can you move the door manually without the actuator hooked up?

Roy

Then replace the actuator. It may be failing under load.

Roy

You are welcome.

Always glad to help.

Roy

Welcome to 2CarPros.

Here are the directions for replacement. It is located under the dash on the HVAC box. See the pictures for location.

MODE ACTUATOR REPLACEMENT
REMOVAL PROCEDURE

1. Remove the air temperature actuator.
2. Disconnect the electrical connector from the mode actuator.
3. Remove the mode actuator retaining screws (1).
4. Remove the mode actuator.

INSTALLATION PROCEDURE

1. Align the mode valve levers with the cam slots.
2. Install the mode actuator.

NOTE: Refer to Fastener Notice in Service Precautions.

3. Install the mode actuator retaining screws (1).

Tighten
Tighten the fasteners to 1.4 N.M (12 lb in).

4. Connect the electrical connector to the mode actuator.
5. Install the air temperature actuator.
6. Recalibrate the actuator. Refer to Re-Calibrating Actuators.

Here are the re-calibration directions.

RE-Calibrating Actuators - HVAC System - Manual
Vehicle Heating and Air Conditioning Testing and Inspection Programming and Relearning RE-Calibrating Actuators - HVAC System - Manual
RE-CALIBRATING ACTUATORS - HVAC SYSTEM - MANUAL
CALIBRATION PROCEDURE
Use the following steps to perform the calibration update.
1. Turn OFF the ignition.
2. Remove the battery positive voltage circuit fuse of the HVAC Control Module.

IMPORTANT: The module memory will not clear if the battery positive voltage circuit fuse is installed in less than 60 seconds.

3. Wait 60 seconds.
4. Install the fuse.

Check out the diagrams (Below). Please let us know what happens.

The mode selection is done through a series of air doors that are operated by vacuum. When there is either a partial or total loss of vacuum, the system will default to either defrost or on some vehicles, heat. Acceleration can also have an effect on the doors for the same reason.

This guide will help

https://www.2carpros.com/articles/air-vents-stay-in-the-defrost-position

Look under the hood for a small black plastic hose coming through the firewall. Follow it to the vacuum source looking for any breaks, cracks or leaks. Also follow any other lines that branch off because they may go to a vacuum reservoir (storage tank) and a leak there will cause the same problem. Using a vacuum gauge to determine if you have full vacuum at any given point is the best way to find it. You can cut into the line anywhere and splice it back together with a piece of vacuum hose. Find the broken line, you found your problem.

Check out the diagrams (Below). Please let us know what happens.

Hi,

The air flow direction is controlled by what is called a mode door actuator. On this vehicle, all actuators are controlled via engine vacuum which is supplied from the engine intake manifold via a black vacuum hose. That hose connects to the rear of the controller in the vehicle where you select air flow directions. Then, based on your selection, engine vacuum is routed to the different mode actuators which open and close different doors allowing the air to flow in different directions.

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Since you are getting air at both the defroster and the floor, I suspect the vacuum supply from the engine has failed. In most cases, the plastic hoses crack and break off. So what I need you to do is simply craw under the dash and locate the vacuum hoses to the rear of the controller. Locate the black supply hose and remove it from the controller. Start the engine and place your finger over the end of that black hose to see if there is a vacuum (suction) available from the engine. If there isn't, we will need to locate where the break has happened.

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I attached a pic below that shows the different actuators and vacuum lines. Note that I highlighted the supply. That is the black one you need to check.

Let me know what you find or if you have other questions.

Take care,
Joe

I'm not sure what you are referring to. Are there vacuum hoses going to something at that point? If it is just a cover, I don't see how that would cause this.

Joe