Damn rear heat/air

My dad owns a 1996 Windstar GL and whenever the rear air or heat is turned on it puts heat out of the floor vent and air cond. out of the roof, it doesn't matter if you turn on the rear heat or the rear air. That and the GD interior lights will not go off until you get it up to 15 MPH. I know those lights are set up on a door switch but that's another thing I CAN'T FIND A SINGLE DOOR SWITCH ANYWHERE Please help me B4 I get pissed at this thing and blow it up or sumthang.

Check owners manual.Read-read,and read again.
I would suggest, anyone who owns a Windstar should invest in a Chilton manual.You could go to the library,but you will make regular trips
IMO

As I understand the early model Windstar set-up, there is only one blend door in the rear unit ... one door that simultaneously "handles" temperature and up/dwn direction of air flow. It sounds to me like the blend door pneumatic actuator is not working ... or perhaps the blend door is stuck in some middle positon. This is all waiting for you under the LH lower rear quarter trim panel. May be just a leaking or plugged vacuum hose.