Lexus SC430 Air Conditioning

lexus

#1

Our 2002 Lexus SC 430 air conditioning system has a mind of it’s own. It blows hot air when it 90 degrees out side. I believe the system thinks it is 30 degrees and needs hot air. I have replaced the compressor, evaporator and the circuit board that controls all of the air conditioning modes and the system is still not operating properly. Has anyone had a similar problem or can suggest a solution?


#2

Does it ever blow cold air? Did you check the compressor clutch relay?


#3

Could it be the blend door or temp door motor is inop. Can you hear them driving when the modes are switched.


#4

The problem might be with the expansion valve.

http://www.rockauto.com/catalog/moreinfo.php?pk=1003205&cc=1377817

The expansion valve is what meters the amount of refrigerant that enters the evaporaor as a gas. The disc on top of the expansion valve opens and closes the valve depending on the temperature inside the vehicle.

Tester