Rear a/c heat
 

I am only getting rear air flow from the floor vents and nothing from the roof... My passenger van is converted to a work van and i have shelving bolted in .. so getting to the panels is going to be a job itself. .. I am trying to find out where the vacuum line that activates the Vacuum motor comes from and the routing of it .. THE FRONT WORKS AS IT SHOULD.. I want to test for vacuum but not sure where the line starts or runs... the ford vacuum diagram does not show this.