Air conditioning not working. Blowing cool air in the back and hot air in the front.

low Freon sometimes the front seal on ac compressor goes bad take it to a shop they should have a leak censer to find the leak

Thermostat is sticking or heater core is blocked.do not keep running it or it is going to ruin the engine. It is running hot regardless if is blowing cool or hot air. Do not keep using the car.

1--BLEND DOOR NOT SEALING PROPERLY
2--FRONT CONDENSOR PLUGGED UP WITH DEBRIE
3--FRONT CONDENSOR NOT TRANSFERING HEAT (SPRAY WITH GARDEN HOSE WHILE ---RUNING SYSTEM IF IT WORKS BETTER CONDENSOR MAY HAVE TO GET CHANGED
4--WRONG CHARGED WEIGHT IN SYSTEM
5--COMPRESSOR CYCLE TIME NOT CORRECT
6--IF COOLANT CABLE VALVE ON SYSTEM MAY NOT BE CLOSING CORECTLY
---TRY PINCHING OFF THE COOLANT LINES TO HEATER CORE

More than likely, you have a blend door actuator problem. Locate the faulty actuator under the dash, usually on the firewall, and replace.

On this car the blend air door is known for cracking at the swivel point that the motor sets in to change it back and fourth, Trust me as a 24 year ford tech, You need a new heater box to repair this issue

your split manifold located on the firewall that sends and directs the refrigerant from the front and rear depending on your setting on the dash is plugged or the climate control on the dash is not responding and there could be a fuse,relay,broken wire,but there cant be a leak or either side wouldn't cool

there is a blower in front and back and the blower in the front is most likely blown

It may be getting low on freon sometimes they leak out

Sounds like your freon has leaked out and your heater blower resistor is burned out. Deffinitly take this to the dealer.

I know from experience that if the coolant is to low ( not just the freon levels in the compresor but the antifreeze/coolant level as well) the AC system will not cool and will blow hot. Check the coolant Antifreeze and freon levels, even with the Coolant being a little low my 1998 Ford E150 Van will blow hot. After you have ruled out of these possibilities and the chance it is the thermostat most likely the problem is what Ford calls the "Flap" it controls the air flow through the vent system when you switch from Heat to AC. When the Flap is working it closes off one systems air flow so as to not interfere with the current climate selection.