yeah... you can use any old check valve and just T off to the other 2 connections (like I did) if you wanted (I did have the parts on hand to do that so it saved me a trip to the parts house).

89 grand marquis a/c problem
 

well i found the problem with my a/c the vacuum air control switch on the head unit was bad which they do not make anymore is bad i took it to an a/c shop and 2 days later they found the problem after i told them to check the part.

search for blend door lever when trying to find one. that's what it took to find the one for my 88.

that is if you're talking about the part that has around 8 vacuum lines plugged into it.