2000 Windstar A/C question

2000 Windstar SE
3.8L eng

The A/C was not cold beginning of spring. Added R134 to correct level (Wal-Mart spray can type with guage not professional setup.)
The question is that the rear A/C seems cold but the front is only slightly cool. Today 80degree outside the air from rear vents = 64, but from the front is 78. The dash control is set to Max A/C and full cool.

Is the A/C all run off of one compressor/system (I assume so.)
If that is the case I may try looking at if the heater block is not switching off completely causing heated/conditioned air to blow.

Any help is appreciated.

I will give you a bit of a primer ... but you will find much on this forum by searching.

Yes: there is only one compressor, and one condensor coil (near radiator) .. but a front and rear evaporator coil. So the two evaporator coils (the cooling coils) are in "parallel" ... the refrigerant is split into two streams supplying both coils. The evap coils are controlled differently so it is difficult to predict if both are at the same temperature ... touching each coil is the easiest way...or touching the steel tubing nearby.

But there is another important factor: at both the front and rear of the cabin, separate temperature controllers attempt to meet your selected temperature by mixing circulated air thru the cooling coil and the heater coil... this is done by movable "blend doors". Blend doors, actuators, etc ... all can be problems on their own.

Have fun!

In my experience, a system that is low on refrigerant will give cold air in the rear while delivering "less cool" air in the front. It's due to the different methods of creating the temperature drop used in each of the evaporator paths.

However, I've also experienced malfunctioning blend doors causing hot air to blow from some vents. I would be sure to check that the blend doors are not the cause before addressing the a/c.