Heater controls will not work correctly

What is your question?

When engine is cold I turn to auto controls to heat and it goes to the coldest setting of 60 degrees I have to wait until I can adjust it up one or two degrees and then let it warm to that temperature then adjust up a few more degrees and hopefully can adjust to desired temperature

What makes this problem better or worse?

After the truck heats up I can turn knob little at time to increase the temp control with a space of time in between adjustments

How long has your 2004 GMC Yukon XL 1500 had this problem?

A while but now it takes a long time to get to hot. Driver’s side will not heat up until 90 degrees