They are *mostly* independent and will work fine with no connectivity, but you can get some additional control of them via the ECU if you chose to do so. Factory inputs to the SW20 EHPS controller (that matter) are vehicle speed, and PSCT (PS cutout signal), as well as a PS pressure feedback switch that functions like an idle up request. The PSCT signal you can use to cut steering assist fully in certain situations (defaults to on, so obviously you can leave it disconnected if you dont care), an