Originally Posted by RonD
Shouldn't matter, there should be an external check valve on the vacuum line that goes to the intake manifold.
You can test if there is an internal check valve on one of the ports by blowing thru it.
If you can blow thru each port then no internal check valve.
If you can only blow thru 1 port then the OTHER port has the Check valve and that would be connected to intake manifold
thank you very much ,turnes out my lines were in the wrong ports ,reversed them and reconected a hose under the glovebox and my ac is working great , THANK YOU VERY MUCH for the advise !