Air blows out all vents no matter where it is switched to heat or ac defrost, floor

If the air flow cannot be controlled from vent/defrost/floor you may have a blend door issue. This is an electric motor that operates a door in the heating system to control airflow. There are usually 3 motors controlling airflow direction,heat and recirculation. The Ac not blowing cold may also be another problem. If the AC is operational, the compressor will be engaged and the Ac low pressure line under the hood will bw cold. If this is all ok then a blend door issue should be suspected

check your fuses then the blend door motor

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you have a vacum line lose under the dash for the heater or the switch is dirty

Possible bad blend door actuator .some gm cars can be relearned to the new climate control head

I think your problem is the head unit that selects where the air comes out ie. Face, floor, defrost, or hi-level face and floor. If that's not working then it will not let you switch location that you want the air to come out.

go by liquid coolant and check ur heat and ac fan it might be stuck or broken

Sounds like a vacuum activated switch. Your engine vacuum is used to open and close little doors in your vents. If a hose is loose or disconnected or the electronic controls that tell the switch to let vacuum thru is not working, no air will reach your defroster vent at the windshield. Does the switch that controls Vent, Heat (sends to the floor), AC and MAX AC do anything at all? If they do, you may have a specific switch problem. If you switch from Vent to MAX AC the sound of the air flow should be much louder. If the switch isnt changing where the air blows, it is leading you to the problem. Either the switch is bad or the supply of vacuum to the switch is not there whether it is a loose vacuum hose or a disconnected one. Happens often when aftermarket stereos are installed and the installer disconnects something either by accident or forgets to reconnect it.

Sounds like your selector switch is messed up to select where you want the flow of air to go. When you turn the switch to where you want the air to go does it work on floor and when you turn the switch to vent it doesn't?

Does it still blow out the floor and defrost when you set the switch to those positions or does it alway blow out the defrost no matter what? If you can get air to blow out to the floor, then it sounds like you lost the switch that controls the airflow to the vents. If it only blows out the defrost, then you probably lost the vacuum to all of the switches. When the vacuum is lost, it will only blow out the defrost. Check the smallest line on the vacuum distribution block located in the corner near the brake master cyclinder. That line provides the vacuum to control the direction of airflow within the cabin.

common problem, check under dash by the gas pedal if control arms are muving went selecting from ac to heat cuz this it is the control for the vents to go from ac to heat and to defrost.