HVAC Blows out all vents

[VOLTAGExDT]

Been every where online searched everything.

I have air out all vents regardless of selection. However the selection switch does make whatever mode slightly stronger. I have verified the door actuator is moving as well I can see it move the levers. I have also moved the levers by hand without any change in result. Any ideas?

98 tahoe
5.7

 

[lesterl]

Same issue here...... 1998 Sierra..... havent taken time to tear into it, but makes running the AC when it is raining fog up the window so I carry a heavy shirt to throw up on the dash when I dont want defrost, perhaps we can fix ours together, I suspect mine has a fault internal to the baffling as I had one pop loose when I got her a couple years ago.....

 

[bostonclover]

I am trying to fix this issue. Any help?

 

[lesterl]

watch the motor and linkage(s) on the side of the box above the accelerator pedal, turn the mode switch from end to end and watch and see if any of the linkages are compressed (mine was jammed).....