2003 Lexus GS430 Q&A
2003 Lexus GS430 Question: Car is stuck on defrost. Won't blow heat or air The two middle vents don't work.
A Lexus Scan tool and some professional grade scan tools have the capability to read trouble codes and carry out diagnostics on the heating/climate control on your car. The system uses servo motors, electronic control unit, and a controller. Hard to guess what wrong without being able to carry out tests on the system. - patrick mannion