i believe it is that the freon is low. the way you can check is drive the car, put the temp selector for both sides at full cold, make sure the ec button is on, this will turn off the compressor, if during this time the drivers is still warm you may have a vacuum element or control problem or possibly a duo heater valve binding open or not seating inside properly. if during this test you find that the temps are closer to the same now, what is happening is the froen is low and it is not allwoing proper circulation of freon to the drivers side, not allowing for proper cooling, i have also seen a partially clogged receiver dryer cause similar problems. please let me know what you find. Ray