Everythang works on my 2002 chevrolet trail blazers a/c except when I want the air or heat to blow out of my main front vents anything comes out. It will switch from the defrost to the floor vents no main vents when I’ve got the control on defrost it’s fine it blows threw the windshield vents when I switch it to blow threw main vents it comes out floor. There isn’t any popping sounds or anything coming from dash like anything is broken. Is this a computer problom type thang or can i just change out the acuater mother to fix ? Thanks for your time

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ID Status Date Year Make Model Transmission Type A/C Controls Public/Private
#13277 Closed 2002 Chevrolet Trailblazer LS public

A/C problom with the vent don’t blow out air in a couple vent modes.
Sparky

You might want to try a recalibration of the actuators before doing anything else.

Important:  Do not adjust any controls on the HVAC control module while the HVAC control module is self-calibrating. If interrupted, improper HVAC performance will result.

Alternate Method (w/o Scan Tool)

  1. Place the ignition switch to the OFF position.
  2. Connect all previously disconnected components.
  3. Remove the HVAC B fuse for a minimum of 10 seconds.
  4. Install the HVAC B fuse.
  5. Start the vehicle.
  6. Wait at least 40 seconds for the HVAC control module to self-calibrate.
  7. Turn the ignition off for at least 10 seconds but no more than 30 seconds.
  8. Restart the engine and check the a/c operation.

If this does not work the mode actuator is the likely cause of your problem. However if any actuator fails to calibrate the recalibration will not complete and all actuators can be affected.  Really should be properly diagnosed with a compatible scan tool.

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