Cherokee Heater Controls?

Our 74 Archer has the standard two-lever horizontal quadrant for heater and
defroster control. The last time I flew it, the heater was stuck on.
Moving the lever had no effect. Our feet were actually hurting it was so
hot. The defroster valve seems to work fine.

Yesterday, I took the little bridge off the lower cowl so that I could get
at the flapper valve. The valve moved fine, when the control lever was
moved, and it could be moved to the closed position by pushing the valve
flapper lever directly, but it was very hard to move the last 30 degrees.
The problem seems to be too much friction in the cable, although it moves
fine using the control for the rest of its travel (fully open to 30 degrees
from closed).

My question is, how do you get the cable out to lubricate it? It was too
hot inside the cabin to let me work in there, so I didn't look under the
panel. Does the control quadrant come off, once the plastic facia is
removed? Does anyone have a drawing of how it's attached. Thanks.

--
Bob (Chief Pilot, White Knuckle Airways)