Why does my 2003 Chevy Silverado only blow air out the defroster setting?

[Karen R]

Is there some kind of mechanism or motor that moves something to redirect air from defroster to under-the-dash to front-of-the-dash? I'm suspecting that whatever does that is not working? Can I replace it myself?

 

[roger]

it would be your blend doors but unless you're a patient technician you wont be able to do it yourself. might as well take it into a shop.

 

[seven_up_the_uncola]

Hello ,

Usualy a cable moves the Damper Doors . Or a Vacuum operates the Damper Doors . If the lever that controls the Damper Door moves loosely when you are adjusting ,it could be the cable may have broken off most likely at one end or the other . One end will connect at the lever you move , the other end connects to the Damper Door directly . If the Damper Door is operated by Vacuum , most likely the hose fell off the Vacuum Diaphram which is located near the Damper Door . Also the will be a series of hoses connected to the area of the control board from where you operate the heat and cooling from . Behind that control board could be be where the hoses fell off . You will need to perform a visual inspection . Also , if the Damper Door is failing to move and it is controled by vacuum be sure to check the Vacuum Diaphram .. it to could be ruptured and need to be replaced . There is a way to check the Vacuum Diaphram . Ask an auto store person to give you instructions . But you need to activate the Vacuum Diaphram by removing the hose fom it and press the plunger or pull the plunger until it stops .. hold and plug the stem the hose was removed from with a finger ,, now release the plunger . If the plunger stays and does not move ... the Vacuum Diaphram is good to use .