Id rather stab myself in the eyes with s pencil than do that again

Anyway, the manual dial selector for the fan doesn't turn all the way to the face setting.
It's about 4 clicks too short. I can put force to it and it goes but when I let go it moves back 4 clicks to the face and foot setting. Is the mechanical bit bit for that down near the heater core or is it somewhere else?
The heater also doesn't get as hot as it used to. Are the two related? Ie have I not put it together correctly?