help with broken part that fell out under dash

[JB Z71]

So this part fell out from under my dash of my 2007 classic 1/2 ton Silverado this morning onto the drivers side mat. Now also, the ac blows hot, not cold. (Was ice cold yesterday) Any body know a name/ part no for this would be much appreciated. Is it a diy job? Is there a diy written anywhere someone could point me too? Thanks in advance.

 

[dard6555]

Did you ever figure this out?