A/C Knob..

My A/C knob isn't clicking into place anymore.. Any ideas? We had to take apart the dash to replace the heater core.. Now the knob doesn't function correctly..

is it just the nob? like it still works, but the knob doesn't kinda fall into the setting? If this is the case, check the knob, if the knob isn't clicking into place, then the only real option is to replace the knob

Yes.. the A/C, defrost, max a/c still work fine.. It just doesn't click into place.. I don't understand why because if worked before we took the dash apart...