ac and heat knob turns but the number does not move. We tightened the screw and

The nut does tighten up but the temp. stays the same. I have been looking at different sites and we are going to look into soldering the 3 point together again. I hope that works. You know with so many cars having the same problem I am surprised that no one has brought forth a class action suite against them for the problem with control knobs.