just bought a 70 lemans and the lever to switch to heat or defrost is stuck in off positions, before I make it worse has anyone had this happen, what was it and how did you fix it? thanks

Best option would be to replace the swithch.   Check Ames, Original Parts Group, National Parts Depot to try N find your best price.  Ebay would be another source.

Frank’s Pontiac parts too!

I need to fix my heater and a/c controls in my '70 lemans also. Isn't the blend door controlled by vacuum somehow?

If your blend door is like mine, mine is controlled with a cable that runs from the control to the top of to  physically open the door. Remove your glove box door and box, and you can see the cable in action with a flash light.

yeah I disconnected the cable and the cable and the lever at heater box work ok, I see the speaker under the dash is gone thinking maybe they dropped something on it and its jammed just tough to see

Factory speakers were often made with thin / inexpensive paper. Car companies are definitely not audiophiles. The stock speakers were easily destroyed it you did much under the dash or if water got to them. You can get better after market replacement speaks that will bolt in it's place.