It worked fine yesterday now today my slider will go from off to max then no further.Then next one is normal then it goes over to the heat/defrost side.It won't go over there it's stuck I'm gussing it's a cable thing under there.Where do I look to see where it's hanging up?>

[QUOTE=zgator]It worked fine yesterday now today my slider will go from off to max then no further.Then next one is normal then it goes over to the heat/defrost side.It won't go over there it's stuck I'm gussing it's a cable thing under there.Where do I look to see where it's hanging up?>[/QUOTE]

I'm not good with this but I believe there are two ways to see.

First, Take out your glove box.  In back on the left side there is the heater & A/C cable on top of the ducts.  The cable is attached to a slider which opens and closes the vents.  See if the cable has slack or the nut that holds the cable in place is loose.  If so, thighten the nut or replace it.  Gm # 381700 for nut.

Second.  This is tough.  Your going to get under the center console.  See if either sliders came off each track.   Where the A/C vacuum hose attaches to the slider cage.   Sometimes the sliders break and will not let you move from side to side.

Good Luck. 

Thanks for the info i will try it tomorrow. by the way your car is exacactly like mine, and was this picture taken in the smokey mountains

In my '81 when I had the centre console apart recently, the Off/Max/Econ/Vent/Htr/Demist slider (ie the one closest to the engine) operates a rotary vacuum selector and a built in electrical switch (Air Con on/off). The cold/warm/hot slider (closest to the handbrake) operates a cable.

Pretty impossible to get to the rotary vacuum selector gizmo without pulling centre console I'm afraid. Good luck. I have a few jpegs of what it looks like in there if you want a heads up b4 you start !