MyNameIsJared

I've been having some A/C issues for some time now, and the heat in Fort Worth is just too hot now to ignore any longer.

I have had a hissing noise coming from the dash for a while, and I assume that it has to do with the vacuum hoses that help direct the air flow to the vents. I can change the air flow to any particular vent, it doesn't blow out of all at the same time, but the air won't stay cold for long after adding a little R-134a.

The one mode that eliminates the hissing noise is when it is set to defrost. Would anyone know which color hose might be the one that deals with the defrost vents? I'm not positive about how the hoses work, so any thoughts on the subject is appreciated. I've looked under the passenger footwell and haven't seen any issues there, so before I pull off the access panel in the fender, I thought I'd check with you guys. I've read a ton of threads on the issue, but haven't seen anything that dictates a specific hose correlating to any vent.

I also have the question about the R-134a leaking out. Is that an additional problem, or would that happen if there was a vacuum hose with a leak in it?

Thanks in advance.

n8dogg

There is a black vacuum hose that travels from underneath the battery box/RF inner fender through the dash to the HVAC head unit. This hose is prone to break. Not sure if it would cause the A/C to blow warm or not. Sounds to me you have 2 issues, one vacuum leak and one refrigerant leak.

MyNameIsJared

So you think it would be likely I need to pop off that access door in the wheel well, or do you think the whole fender should come off?

Also, do you know if the colored hoses correlate to any particular vent? Just curious if it would help troubleshooting, or if they work a completely different way.

Thanks for the reply.

bjones7131

Vacuum leak has nothing to do with the freon leak and warm/cold issue. If after you correctly charged the unit and it blows warm air later on it means u have a leak, compressor, hose, condensor, evaporator, valve, etc.

n8dogg

I think first you should check the refrigerant charge and make sure it is fully charged. While the system is being charged, make sure you inject dye to help find any leaks.

If you are hearing the hiss under the dash, then I would remove the HVAC control unit and follow the vacuum line til you find the leak.

MyNameIsJared

Ok, sounds like the plan. I'll knock it out next weekend and see where it gets us. Thanks for the help. I'll recap how it goes after I get it done.

Chicago1

http://forums.corvetteforum.com/c5-g...1a147a9f73d5e8

MyNameIsJared

That's good stuff. I looked at quite a few threads already, somehow missed that one. I appreciate it.

Chicago1

No problem let us know how it goes