Why does the climate control output selector on my 2006 chevy express van do nothing when I move it? The air comes out mostly defrost but a little on floor and face levels.

Maybe the vacuum line to the selector is disconnected/leaking /bad. Most of the vacuum controlled systems I have worked with also have a vacuum amplifier somewhere under the hood that increases the amount of vacuum going to the selector.

The are two controls on the heater. One is the blend door and that controls hot and cool, the other is the mode selector door and that changes the place air comes from. You should be able to see those and the area that controls the air in the plenum. The plenum is behind the glove box. Open the glove box all the way and see if the controls are visible. Activate the mode control to see if the lever moves on the plenum, the problem could be anything from a broken lever, bad control, loose control, or something that fell down the defrost vents.

. 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.
• The vacuum selector valve directs source vacuum to various vacuum control motors (18A318). Refer to the Vacuum Control Diagram , System Airflow Schematics and Vacuum Control Chart .
• Two internal, single-pole electrical switches are also controlled by the A/C-heater function selector switch. The combination of these electrical switches controls the electrical supply to the A/C clutch and heater blower motor switch (18578).
• The position of the function selector knob determines the manner in which the system will operate.
• Each position of the function selector knob is detented for positive engagement.
• Vacuum Control Motors The vacuum control motors (18A318):
  
  • are located on the A/C evaporator housing, A/C recirculation air duct and heater air plenum chamber (18471).
  • direct system airflow to the vehicle interior as determined by the remote climate control module or manual override.
  • The five-passenger seating configuration has an additional vacuum control motor mounted on the heater air plenum chamber to control airflow to the rear seat A/C register (19893).
  
  

Mode door is stuck or broken .

One of your deflector door servos or the door itself, is hanging up. To determine this more clearly, run your vehicle for about two minutes and shut down the engine. Move your function selector knob from defrost to floor to panel and listen carefully for a sweeeping sound. if you do not hear this sound you've got to check under the dash for a loose vacuum line or under the hood for a loose or broken line to the vacuum accumulator. The vacuum accumulator is a large black ball on the firewall with only two lines connected to it. One line is about3/32nds of an inch and the other will be about one quarter inch. Check these lines well, for they control ALL the functions within yout climate control. Best of luck my friend, Dana

sounds like the cable clips came off the back side of the heater. Just pop out the climate controls and try to move the knobs, if the black cover on the cable doesnt move their good. Let me know I can help further.

Yes it can be fix. The car has a blend door actuator . The blend door controls the air flow. The clicking noise is the motor trying to move but the little plastic door gears strips out. This is a very common problem. Your local mechanic can fix it.

Good Luck

In every car, there are fins or flaps inside the dash that rotate that distributes the air flow from the blower to the desired opening, ie defrost, floor etc... This flap is controlled by a linkage which is connected to the selector switch. It may be the linkage is no longer connected, or the fins inside the dash are stuck. If the selector switch moves freely with little or no resistence its possible the linkage is no longer connected, otherwise the flaps need to be physically looked at.

Does your vehicle have manual or automatic climate control ? The blower motor control processor may be the problem .
Chevy GMC Blower Fan Stuck On

Try checking for a vacuum leak.