2006 Pete 379. Trailer supply airline has no air. First thought was dash valve, push it in and release it I hear air moving and releasing. Pulled line off at tractor protection valve, have air from dash valve down to tractor protection valve. Assumed a new protection valve would solve my problem, it didn't. I am now 3 days into being as confused as a baby racoon.
Which line is supposed to be the line back to the trailer out of this valve, it's a TP5 Bendix, suppose I could have a dud new valve out of the box? Any other ideas what my problem is?