Heater control cables with A/C

[northerngmc]

I am only getting air to come out of the A/C balls on the side of the dash and the centre duct above the radio.

I have tried moving the controls into all possible positions and still only have the A/C vents getting air to them. Nothing at all coming out of the heater/floor vent or the dash/defrost vents.

I have looked up under the dash and the cables are free and moving.

The lower control for heat seems to work fine and I can control the temperature of the air.

The owner's manual states that with the top lever when you move it to the outside air position ( almost all the way to the left) the vacuum control should open the door in the kick panel on the passenger side and when you move the lever all the way to the left, marked inside, the outside air door should close. When I start with the lever all the way to the right, the outside air door is closed. When I move it to the left about in the middle it seems to get a lot easy to push and in the outside position the outside door is not open. If I push the lever all the way to the left, to the inside position, the outside air vent in the passenger side kick panel will open. This is with the truck running. I tried adjusting the cable by pushing it all the way to the right, which retracts the cable, and adjusting the cable end to the full retracted position. Still no better.

Any ideas?

I do have a 69 service manual but it does not really cover how to adjust the cables.

Oh yeah, this is on my 68 C20, 396, turbo 400 with factory A/C. The belt is off the A/C and I am waiting for parts to get the A/C functioning again.