I will try to make this post as short as possible . here is the problem .
My AC blows from all openings . I have read all there is to read about this and here is what i have .
the dual control is good , I know that because i have another C5 and I swapped head unit but problem remained .
the relay / solenoid under the passenger side dash is also good , because I can I can create a vacuum with my mouth on the input hose , and when I change settings on the "mode" , the AC works as it should , only the vacuum line is dead , no vacuum on it at all .
now I have also read about lines going bad becaue of acid leak from battery , but hoses are fine , no problems at all , the check valve works well , and the canister under the fender seems OK ,
Now the problem is that the vacuum line coming to the check valve then splitting to the canister and the solenoid inside the car is dead , it is ran in a bundle of wires under the battery tray , then behind the engine where I lose it ,
so now the question is where is the vacuum source in the engine compartment that this tiny hose is connected to ? and can it be reached ? I think this hose has come disconnected there but I can't seem to find the source .
Thanks a bunch for any advice and help

 

The vacuum hose connects to the back of the intake manifold (passenger side I believe). Supposedly you can reach behind the manifold and touch the hose. However, this is a very tight fit - I couldn't reach it myself. You might have to remove the intake manifold.

If you take the line off the check valve and have someone blow through it you can hear the air hissing out of the leak. I was able to find the location of my leak by sqeezing the wire bundle (where the vacuum line runs through) and waiting till I heard a change in the sound.

Good luck.

 

could not reach it myself either . could it be reached from under the car ? instead of taking the intake out ?
thanks

 

No.. The intake has to come off or come forward but its easy.