Rather, the spring in your wastegate actuator keeps the wastegate closed. The N75 valve only lets pressurised air through to overcome the actuator's spring force to open up the wastegate. Now I don't know if you have a 225 or 250/265/275, but on the 225 the boost will be solely controlled with the N75 valve.
Heavy duty engine wastegate repair kit dki470e16019 . View This TSB. TSB Number: 1103-17 NHTSA Number: 10140743 TSB Date: November 3, 2017 Date Added to File: June 11, 2018 Failing Component: Engine (Pws) Summary: Diagnostic tests - two-filter system, three filter . View This TSB