vent selector not working

[89k1500sport]

alright so heres the problem. i have the digital a/c controls. the temp and fan part work correctly. but the position part doesnt. you push the button on the left to change the position just once and it shows it switching from all the way on top to all the way on bottom, doesnt stop inbetween (not sure if its supposed to?) and no matter what it only blow out of defrost.

so im thinking its one of the actuator motor things, but my question is which one?? i saw 3 of them under there (one on driver side, one behind glovebox, and one down by blower motor)

[hende]

According to an older post I found on here its the one on the driver side. I have not verified this yet, but I am experiencing the same problem.

[someotherguy]

Two problems here, though you didn't say if your symptoms are exactly like that older original post.

The position not stopping in between is normal operation. 1988-1994 for the vent position you push the button once to start it moving, then push it again to stop it. Otherwise it will go all the way to the opposite setting.

If the indicator is moving but the airflow is not changing, the vent position actuator may be bad, or the linkages on it may simply be gummed up. Correct; it is the one on the far driver's side of the unit.

http://www.someotherplace.com/guides/defrost02.jpg

Richard