Suncore's Solenoid Valve is a direct replacement for OEM solenoid valves that are no longer regulating the flow of air from the air springs. They are designed to work with the electrical components of the air suspension system to fill the bellows to the appropriate height. Suncore's solenoid valve unit functions as good as, and usually better, than the OE factory valve that came standard on the vehicle. Once you have installed your solenoid valve your rear air spring will once again work in unison with the other 3 air springs.