How do I get to the blower motor?

What is your question?

I've dropped the glove box and opened the black plastic housing behind it. It appears that the first round-ish housing behind the glove box is empty! When I turn on the power on the van, and turn on the switches for the AC and blower fan, the humming and vibration comes from the housing a little to the left and above the empty housing. I cannot see any way to get into the rest of the housing. Any suggestions?