HVAC will not work unless I press the bottom part of the dash

My Chevy Cavalier's blower fan wont work unless I press on the bottom part of where the
glove compartment is. When I stretch my legs while sitting in the passengers seat and
press the black rectangle looking thing under the glove compartment the fan will work
like normal, but when it's not pressed it doesn't. I havent messed with it or looked at it but
since winter is approaching, I really need help figuring out how to fix this problem. Any
help is greatly appreciated! Thanks in advance!