Heater Fan Won't Work

[flintsters]

Admittedly, I am not the most mechanical person. However, I bought and installed a new receiver that has a backup camera for my daughter, who recently purchased a 2014 Impreza. I had a heck of a time getting the center dash out to change the receiver. When wrestling with it I noticed that a little white piece became disconnected (see picture). It goes to the fan speed control knob. It went back into position fine and I didn't think too much about it. Well, when I put everything back together and was showing my daughter she noticed that the fan didn't work. It was getting power, but just wouldn't turn on or change speed. I figured it must have come undone when reinstalling but it was still there. Does anyone have any suggestions about how to get this fixed?