[tripletdaddy]

Since the Windstar has two evaporators in it, I would think it could have two eveporator core orifices. They have two filters in them, so it could be possible that it is plugged and the other one for the front is not. This is the only explaination I can think of at this time. If you are sure you have air going across the evaporator, but it is not cold but the front is, something is blocking the refrigerant flow. Sorry it doesn't sound too good.

Are you saying that even with being able to switch the air direction, you are getting the SAME temperature air out of the TOP as the bottom? The top won't cool down over time? That doesn't sound right. Hopefully, somebody has or could send you a vacuum and electrical diagram of the back system and a schematic of the air handler with its contols etc. On some years, they put a valve underneath to turn off the coolant to the heater, though I don't know how that helps. Maybe your system has something like that for the rear ac. I'm fairly certain my 95 doesn't.