Originally Posted by srswain
Mine comes on all the time and the truck wont start untill the pump kicks off. Also right before the pump kicks off there is usually a light clicking noise from the dash. Never have been able to pin point it. It only does this after sitting for a while like over night. I have been thinking there is a vacuum leak but not sure what else could be causing this.
you sound like you are talking about the electric pump on a superduty. OBS trucks still use a manual belt driven pump. If yours is not starting when the pump is running check your battery cables for good connections. Also if you were have a vacuum leak problem your ac vents should default to defrost and not blow out of the regular vents.