The Saab automatic climate control or ACC was designed to regulate cabin temperature and ventilation by just setting one adjustment, the temperature. The ACC system is then to take in account outdoor temperature, sun intensity and cabin temperature to fulfill the drivers request. The ACC can also be run in a ECON mode this selection simply keeps the A/C compressor from running saving on fuel. On the early 9000 1986-89 we had a two button system or ACC1 with no off switch this was not a popular design and Saab has used a system utilizing a off button since 1990 called ACC2.