I get that. I have spent hours searching for air leaks on transport trucks which have miles of air lines, fittings and air bags unable to find any, yet the customer insists it looses air over night. Sometimes you have to add extra soap to the water spray everything down and wait a few minutes. The tell tale is sometimes nothing more than a very slight foaming at the leak. Also check the exhaust ports and or open ended lines near the solenoid valves. Cover the hole or end of hose very lightly with a wet soapy finger. Its possible the valves are leaking internally and allowing air to escape through the exhaust port. If your not sure were they are with the compressor assembly uncovered, lower the pressure using the buttons on the class control panel. As you do this you will hear were the air is escaping as the system dumps air, these are your exhaust ports. they should seal up tight other than when dumping air. If air is leaking out of these other than when lowering the suspension than the valves are faulty and need to be replaced.