1999 Windstar with no rear heat or air

I have a 1999 Windstar that has no rear air or heat. Nothing will come out of the vents at all. I have checked all of the fuses (I think) and have no idea where to go now. The front air and heat are working great but nothing in the back at all. Anyone have an ideal?

The rear motor could have went bad. On my 2001 its in the very back in the rear hatch area on the drivers side. wish i could be more help.