Hi I'm new to these forums, I just bought a used 2007 Hummer H3.I downloaded the Manual for it but for the life of me I can't find the answer to what I'm looking for so I thought I would ask here to the people that would know.
On the climate control panel with the 3 ***** I understand turning the ***** to control the heat and the flow but I can't seem to figure out what pushing the center of these buttons does. When I push in each button a light comes on but I don't see anything different happening. Can someone tell me what each of these buttons do when the light is on. Thanks in advance for any help.

 

The one on the left turns the A/C on, the one in the middle turns the "recirculated air" on (as opposed to fresh outside air), and the one on the right is for the rear window defogger (pages 170-173 in your manual).