Question: A 1997 Buick Lesabre that blows cold on one side of the car and hot the other side. It is a dual control system. What causes this to happen? The drivers side dash vents was blowing cold and the other side hot and now both sides are blowing cold with A/C on or off.
Answer: Well, first off check the coolant level. A low level would cause the heater core to be inefficient, and only warm the pass. side. If low enough, it would not be warm anywhere. A restricted heater core would do the same thing. You can flush it out with a garden hose. If that is OK. you may have a problem with one, or now both of the temperature door motors. Your system may have a separate door for each side.
Turn the fan on high and change the temp control from full cold to full hot. Put your ear up against a driver or passenger side vent and listen for a change in the airflow. This would indicate that one of the doors is moving, so one side should change temp. Do this on both sides. If you do not hear any change, then the door motor on that side is faulty.
If one of these seems to be faulty, you can try to disconnect the battery for a few minutes, then reconnect and start. Let it idle for 3 minutes before touching any A/C controls. This is an HVAC system reset and may correct the condition for while, but would still need to be repaired.
But again make sure the coolant is full first.
Buick Lesabre A/C Blows Warm Drivers Side
2004 Buick Lesabre the a/c blows cool on passenger side but not on drivers side. does not have dual controls.
Answer: When you do not have a dual zone A/C system and it blows warm on drivers side, this is caused by low freon charge. The evaporator is the part of the system that cools the air. it is located on the passengers side of the dash. When the freon charge is low, the system can only produce cool air, and since that slightly cool air has to travel to the other side of the dash to get to the drivers side, it warms up as it goes because it is is not cold enough to stay cold. Also if the car is warm inside, the dash ducts are warm and will overcome the cool air passing through it. If the freon charge is full and the A/C is producing good cold air, it is not effected this way.
Most people, and even mechanics don't believe me when i try to explain this to them, but believe me, I have seen it several times. You just need to add freon to the system.