Vent Selector Knob does nothing

[slikrider20]

Hello all, i have a 2000 Pontiac Grand Prix GT. 195,000 miles.

Have a problem with the vent selector knob. No matter where i set the knob, it seems to distribute the air throughout all the vents evenly. Nothing changes when i turn the knob. The blower works fine on 1-5, and the temperature control also works fine. My cruise control works. What do you guys think the problem is? I've had a hard time finding much information on this on the internet. Thanks in advance

[Fivefingerdeathpunch]

Sounds like a blend door issue.

[tech3627]

It is very common to have the knob itself brake. Pull the knob off and look to see if it is cracked around the center. Sometimes the metal sleeve stays on the shaft also.

[Turbocharged400sbc]

vent select knob probably means its a non auto climate control head so im gonna say its a vacuum actuator

check the vac supply line/resevoir bulb for vac, the line should go across from the pass strut tower to the 3 way vac tee on top of the blower

ive seen the knob break but thats usually after the initial problem as they "beat the **** out of it" trying to get it to work

[slikrider20]

I will check the things listed so far, thanks for the ideas. And by the way, it is a non auto climate control.