What is the purpose of each solenoid valve on an NA S5? I think there are five solenoid valves (correct me if I'm wrong) and each one has a different color sticker on it for identification. I know how to check the solenoid valves to find out whether or not they work by applying battery power to the valve and blowing air through 'port b' and checking the air flow through and out 'port a.' I'm just wondering what each one is for?