Alright, this is just embarrassing. I can't get the shaft to stay extended.

My old vent selector was snapped off when I got the truck (a 96 1500), so I bought a pack of Dorman replacements online. The moment I touched the shaft, it recoiled into the panel and made a hissing sound, and shut the vents off completely. It doesn't turn at all in this recessed position.

I can get it to blow in the defrost+foot setting by pulling on the shaft with pliers and rotating it to a point between options, but any touch causes it to snap back down. The hole on the **** barely reaches the shaft in this position, and won't turn it anyway.

How in the world do I get the shaft to stay put so I can press the new **** on?

 

Replace the vac switch, It's broke.

 

Thanks moparite, sorry I didn't reply. It appears that I have a hole in the vac line that tees off into the cabin (passenger's side).

Any idea if replacing this alone will resolve the retracted shaft, or should I be watching my local junkyards for the switch panel as well?