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

 

[SunlitComet]

Possibly if you can remove the mode door motor and move them by hand and it still is not right then the door panel may be broken off or be jamming against something. With the motor off move your dial and watch motor at the same time make sure the motor shaft moves all the time the dial is moving. If it stops along the way then one of the two is bad. A voltmeter can narrow down which one. If no signs of non-movement watch the total angle sweep of motor and make sure manual lever shaft movement by hand equals that. If not you may need to tear into the hvac box for inspection.

Enjoy.

 

[VOLTAGExDT]

The actuator does move the complete distance and holds. As well by hand I can move it the whole distance without and issue.

 

[SunlitComet]

If you meant the linkage to then the box will likely have to come out for inspection inside.