Hi all,

Yesterday out of the blue on my way home from auto zone, my A/C system decided to only blow air down in the floor vents and a very small amount through the defroster vent. Nothing comes out of my actual A/C vents on the dash, no matter what temperature setting or direction I turn the dial to. I think a vacuum line came loose or popped, but I'm not really sure where to look. Where are these vacuum lines, and what's the best way to check for a leak? Shoebox, got any diagrams or good pictures of this kind of stuff? I'd sure like to avoid taking this to a mechanic to track down.

Thanks!

 

I'll give you my standard reply that I already have written up (I guess I need to put in on my web page) .

An easy way to tell what part of the system may have trouble is to go to the vacuum check valve and test the lines back to the mode selector and to the vacuum canister. If you have a hand held vacuum pump, it would be pretty easy. What you want to do is remove the hoses one at a time and apply vacuum to each and see if it holds. The line to the intake manifold will have to be removed at the manifold and plugged back toward the check valve for you to test the line for leaks. You can test the check valve, too. Sometimes it cracks and is the cause of a leak.

If you find a leak on a particular hose, you will have to trace out the cause on that section.

 

Shoebox,

I took a look at that vacuum check valve, it's got cracks all over it.. I hear a good solid vacuum coming from the canister, so I'm going to head up to my dealer today and buy a new check valve. Hopefully that solves it. If not, I'll continue the process by checking the lines individually. Thank you for your help

 

Thanks, Shoebox! I tracked that valve down, saw it was cracked, tried to remove one of the hoses, and the valve pretty much shattered in my hands.. I bought a new vacuum check valve from the dealer today (an amazing $5.90) and popped it in - worked like a charm. Many thanks for your articles and diagrams!