I don't think the 108/109 has a blend door (the AC is a completely separate system that uses only the 2 front center vents). It's been a while and I don't have one anymore, but I'm pretty sure you have fan speed, floor or cowl (and far left/far right vent) distribution, and 2 valves, 1 for passenger's side heat, and 1 for driver's side heat.

When you put the "Defrost" setting on it's full heat straight at the windshield and the top 2 vents. Can you feel any air coming out of them? Note that nothing will come out of the 2 center AC vents when using heat.