Heat/fan control knob - no heat/air at all & the knob won't even turn??
For a couple of years, the heat/air control knob only worked on a couple of settings (3 &5).
Then it would work intermitently - suddenly it would turn off then turn back on. Recently, it
has stopped completely. I replaced the knob thinking it was stripped, but now it won't turn
at all and no air/heat blowing. Any suggestions?