For starters, I have a 2006 Cobalt SS sedan (2.4L), with 70k miles on it. In said vehicle, I have no AC anymore. I've run through this and a few other forums to try and figure it out, but to no avail...

The status at the moment is simply that I have no cool air, and that I can tell, the ac clutch never engages (I looked while idling a few times, and have never heard the click or 'tone in the engine' change during any other driving). I tried to recharge the system initially (the system pressure was low, and it has taken in some r134), but that made on change (and is when I first noticed the ac clutch wasn't engaging).
Here's a little 'status' info if it helps much...

- The blower works, I can get a good blast of air, and it comes out of the correct vents
- The high and low pressure ac lines are both hot to the touch
- All the ac related fuses have been checked and are good
- The ac cltch relay under the hood, was checked (it was bad), and replaced (but still no change)

...so, any other ideas? any other relays or little things I missed that might be involved or am I pretty much at the "I need a new ac clutch" point?

 

On my 05 ss/sc the electronic magnet for the a/c compressor clutch went bad. Which is kinda rare. After 4 months I finally diagnosed mine cause I took a 7 hr trip in the summer and I was miserable the whole way there and back.

To check it unplug the a/c compressor power. It is a plug on the a/c compressor. Now with the car running and the a/c fan on, the a/c switch lit up, and the temp on full cold. Plug a volt meter with one lead on negative and one on positive to the plug you unplugged earlier. It doesnt matter if the tester leads are reversed cause you will want to switch the leads if you dont get a reading the first time. It should read about 12 volts. You need a tester with long test leads to get inside the plug. It is kinda awkward and is best to have someone else hold the meter looking for a reading as you fiddle

You can get a digital tester at a hardware or auto store for under $20. Even Walmart has them. youtube "how to use a digital volt meter". Test it first on your battery to be sure you have it on the correct setting and can actually get 12-14.5 volts

I just ordered a new clutch for mine from rockauto cause it was cheaper than getting a whole new compressor. A clutch or new compressor both require removal of the compressor just one is cheaper than the other. With 70k miles you might as well get a whole new compressor. Also our cars have no dryer. I spent 30 mins looking and went to 2 auto stores before I figured it just didnt have one. So I just vacuumed the system and recharged.

Also get a temp guage for the vent so you can get a a/c temp reading when recharging. Should read 60 or under within 5 mins of running. If you dont have commercial a/c pressure guages then bring it to a shop.

 

I'm a little late with it, but thanks for the suggestion. I tried it but everything still tested good though.

...I finally just took it to a longtime friend of the family mechanic and as it turns out, something had punched a hole in my condenser. I hadn't noticed anything leak before because my driveway is riddled with stains of various vehicles already.
My mech fixed it, I made a custom grill to keep anything from punching a new hole there, and now I'm finally cruising with a nice frosty 52 degrees.