my 2017 gmc van heat/ac knob only works on high,

What is your question?

only works on high setting, I replaces blower motor and the blower motor resister. At first, I had to get out of van, open hood and Wack the blower fan to get to run and it only fan on hi setting . replaced those 2 parts and still happening. Now I have to wack the panei in the van were the fan control switches are to make fan run. help.