Heater Control Fix

The one I fixed had a cable at top and bottom. A piece of brass 10-32 machine screw went through the original nylon washer like portion, Nyloc nuts top and bottom retain the cables. No squeaks.
The most important point to stress here... The nylon stem is the engineered point of failure for a blend doors movement fault. Find and correct that fault. Otherwise the operator forcing the control lever will break something else. In most cases the cable will bend/wad up at one end or the other.
If not that the cable sheathe defeats its retainer in some manner.