well its getting hot and my ac doesnt blow out of the right set of vents. It is stuck on the defrost setting. has anyone else had this problem and where is the problem? What am I getting myself into?

 

I had that on my buick once. turned out to be a vaccum leak. I am no expert by any means but it may help ya to look for one!

 

Another vote for a vacuum leak; the windshield defrost is the 'default' setting. Start checking hoses under the dash, and in the engine compartment, but be careful around vacuum leaks; that stuff will kill ya...

Pete

 

if you have a tpi there will be a hose coming off on the intake at the rear (near distributor) passenger side of the car, the hose goes over to a small valve on the driver's side near your maf relays and such. it will have two additional hoses coming off it, one goes into the fire wall (controls vents) and the other goes to your cruise control. check to make sure all those vacum lines are conected or replace the control vale ( less than 5 bucks in the HELP! section i believe) and you should be fine, if not the line must be pinched behind the radio or something.

 

I have a TBIed 305 with the T-5. so do you think the vacuum lines would eb in the same place under the hood as the TPI or would they be under the dash? DO you think a shop would charge much to find the leak and fix it since im looking to change over to R-134a refridgerant? thanks

-matt

 

holy ****! i just re-read the post from 87 formula and my cruise control doesnt wortk either... damn well this could be it i will check it first thing in the morning. man yall are the best.

 

the leak would likely be vaccum not refridgerant. Different kinda hoses and lines. Vaccum lines are tiny rubber lines. One may have a slight crack in it or not be connected at all. If everything looks connected mix up some soapy water and spray it on. If bubbles appear then you found your leak.

 

That will work if the line is pressurized. Bubbles won't appear if the solution is being sucked in. Try a spraycan of ether (starting fluid) and spray it around suspect areas when the engine is running. When you find the leak (suck?), the engine RPM will noticably increase.

 

I had the same situation. I checked lines and essentially drove myself crazy in the search. Long story short, the problem was with the switch at the rear of the HVAC controls (the switch where the vac harness fits over small tubes). I believe the switch is still available from GM.

JamesC

 

found the leak! turns out to be the very first line that comes out of the switch at the intake manifold. it was almost entirely broken off. thanks alot it was so eaSy.