??? 2nd row vents not working

I have a 2000 Chrysler Town and Country LXI which I bought used. The owner manual did not come with the van but I have since order one from ebay (it hasn't come yet).

I am hoping that someone can tell me how to get air flowing from the second row vents which are located on the ceiilng above the sliding doors. I get air flow in the third row and the front (including on the door armrests) but cannot find any combination of controls that open the 2nd row vents.

HELP please????

The vents should already be on if you are getting air from the back set. Check to make sure that vents are open and that there are no obstructions in the actual openings. Aside from that there are no other possible blockages to contend with.