Sounds like you are looking for the air dryer, if you don't have air brakes, you won't have an air dryer. If you have air suspension, most likely you have an electric compressor just for the suspension. It won't have a dryer.
2021 Ram Limited, 3500, Crew Cab, 1075FTPD of Torque!, Max Tow, Long bed, 4 x 4, Dually,
2006 40' Landmark Mt. Rushmore