89 RS v6 . There are two vacuum connections on the back of the dashboard control unit. The heater side works perfect. The a/c side (just two hoses) constantly hisses no matter where I set the controls to. I've taken it apart. put a little grease on the rubberized seal. Made sure everything held tight. Same thing. Tired of playing with it, I bought a brand new one from the dealer. Same problem!

Anyone know how to test it out, or knows how to fix it? Right now I just have it disconnected with a piece of tape across the two lines. All is well, just no a/c. Would be nice if it did work..

 

Are you sure it is the vacuum switch?
It very well could be the connector block that plugs into it.

Seth

 

I can try putting something non permanent like heavy grease on the connector maybe. Haven't tried that yet. Odd thou that just putting a little piece of tape across the vac connection seals it when it's unplugged from the switch.

 

I think that a new vac switch and properly mated vac lines would do the trick.

https://www.thirdgen.org/forums/atta...duct010707.jpg

JamesC

 

In the picture, it would be the one hiding under the temp slider to the right. Will try to locate a replacement connector. Thanks!