Air Hissing from rear

I have a 2000 GC that has 64K. Recently it has started a fairly loud hissing noise when running the rear and front a/c. CarMax mech. told me this was normal for these vans, and that it had to do with something like a vent control that was wearing out. Has anyone ever had this problem?

does it go on constantly or does it die out after a while? You could be losing freon, but only time you could tell is if the rear A/C is not cooling like it normally does.

It is not constant, but dies out. It does come back rather quickly though. The noise is from the rear, but the hissing was coming from the front dash as well a few weeks ago (intermittant). The front dash noise has now decided to quit. Our a/c cooling does seem to not be cooling properly either, but the carmax guy checked the freon levels and all was good. p.s. - thanks for replying!

I have a 2001 T&C with the exact problems. Just starting to find dig into it.

We've got a 2000 GC and had the exact same issue. The hissing would come and go from the front passenger side of the dash as well as the rear air area. Sounded like pressure was building and would then release and stop - only to return again in a minute or two.

Local Dodge dealership finally figured it out and fixed it in March. They had to replace the H valve, A/C lines and O-rings. Here are the part descriptions and numbers right off my invoice:

LINE A/C SU PICK 4677167-AB
VALVE A/C E PICK 4882342-AB
O RING A/C 4882137
O RING A/C 4882136

Parts (including new freon) ran $255 but the labor was $425. They knocked about $80 off the labor as a courtesy but it still set me back $730. The good thing is....the air works a like a champ now with absolutely no issues.

$10 says this is the same issue you guys are having...good luck.

Sounds right on the money - I have it in the dealership right now and they found these items to be replaced and much more (obviously, cause it's under the carmax warrenty). Good thing too, cause the A/C repair bill is $1500!! Thanks for the help with this - have a good one!