The default gat positon is closed. Also, FWIW, it is not vacuum operated it is pressure operated. Even with the red tube removed, the truck will defuel at 22-23 psi boost. When it defuels you will get an SES light for a few mintues and an overboost soft code.
Check your lines/connects to the map sensor, and the red line for cracks/leaks/defects. These are things in the "control circuit" for the wastegate.