Air Conditioning Problem - AC blowing hot - 1998 Z28
 

I ran down to a swap meet today and when we jumped in looking for that nice cold air after walking all over, we were greeted with hot air blowing out. It was cold AC on Friday, but this morning it was cold outside so I turned the defrost on and raised the temp.

When we got in the car this afternoon, I switched back to AC and turned it to cold, but the air blowing out is hot, not a hint of cold. And it is hotter than the outside air. If I raise the temp, it gets hotter still, but I can't get it to get cooler.

Anyone run into this? I can't find anything broken - hose, belt, etc. We did make a 135 mph blast just to see what it would do on the way down, but that shouldn't have killed the AC.

Sorry for bringing up an old thread......

But I have exactly the same problem on my 99 C5.

It´s cold outside, but the A/C only blows hot air....even when turned to the coldest position.

The A/C sees to work, tgoug, as the windows get foggy when I turn it off and the fog goes away when tuning it back on.

Any idea WTF the problem is here??

Check the freon pressures. Need to hook up gauges! It should be about 90 psi (either side) when the car has been sitting. The compressor will not turn on if the pressure is too low. Chech the AC compressor fuse in the underhood fuse box.

The compressor will not turn on if there is an AC fault code (check engine does not have to be on).

I would bet freon leaked out, add the stuff with stop leak AND oil in the same can!!!

I checked it and the A/C blows cold on the passenger side.
It just doesn´t blow cold on the drivers side.

Seems it´s the motor on the drivers side doesn´t work?!?

If you mean the air blows thru the defroster vents only then check the little vacuum "T" checkvalve just above the heater core under the hood

Easier to help out if we stick to one car at a time. The Z28 should use a variable stroke compressor meaning that for any a/c position, it's running all the time and not cycling on and off. So first, you verify that the clutch is engaged and if so, that's a pretty good sign that there's gas in it. Next feel the big pipe on the top that exits the evaporator. It should be colder than ambient and if it's dripping a little water, all the better. If that pipe is cold and the clutch is engaged, you may just have a temp door that's stuck. Look for a resistor pod or module mounted on the evaporater case and remove it so that you can look inside. While someone works the slider, you should be able to see a door open and close. If it doesn't, try moving it with a screwdriver. Otherwise, hooking up gages would be ideal, but these systems use an intersecting chart to measure the charge and looking at the high and the low is meaningless without it. So if you want to look into it further, stop by an a/c shop or even Pep Boys for one of their advertised $29.95 a/c tuneup specials.

No, I mean that if I turn the A/C to cold then only the passenger side get´s blowing cold. The driver side stays hot.
If I turn the A/C to "hot", then the passenger side get´s hot, too.

So the passenger side seems to react perfectly, just the drivers side always seems to stay "locked" to the "hot" position.......

Either a piece of ductwork has fallen off or there maybe something wrong with the Dual Zone comfort control components. None of this is used in an F-Body. You might want to post in the C5 Tech Section.