08 Aveo A/C issue...

This summer I noticed my A/C wasn't working and it wasn't that it had no coolant (which it probably doesn't since it always sucked) but the clutch wasn't engaging. I tested the plug that goes to the compressor clutch with a meter and it was dead I even swapped relays and it was a no go. I decided to bridge the relay terminals to see if I could get some action and behold I heard the clutch engage so I determined that it's an electrical issue between the fuse box and cabin.

Im leaning towards HVAC control assembly going bad but I would need to confirm this by obtaining the electrical pinout to the plugs to do continuity & function tests. I cant seem to find information on the assembly or its pinouts does anyone know what they are or another way to go about this?

Just out of curiosity, what is the status of refrigerant in the system? There is typically a pressure switch on the system (many times mounted on the receiver/drier assembly), that prevents the compressor from engaging if there is insufficient pressure - kind of a safety feature, since if there's no refrigerant, there's also likely no oil.....

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Originally Posted by jimzdat

Just out of curiosity, what is the status of refrigerant in the system? There is typically a pressure switch on the system (many times mounted on the receiver/drier assembly), that prevents the compressor from engaging if there is insufficient pressure - kind of a safety feature, since if there's no refrigerant, there's also likely no oil.....

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No Idea I didn't run it long enough to find out but I already knew it was lacking oomph from last year so it is in need of a charge. Thanks for pointing out that there's an interlock which I was unaware of that would prevent it from turning on. There's no onboard diagnostic that would show the status of pressure is there?

Nope, just have to hook a gauge to it in order to determine pressure.
You can pick up the cheap recharge kits at the local parts store, but the reality is if the system is low, you have a leak somewhere - it's a sealed system, the refrigerant doesn't get "used up" at all (yes, I've actually heard someone try and explain it that way). Those kits will at least give you the low side pressure, and you can tell if it's totally dead or not.
You may have some air pressure built up in the system, if you use a small tool to depress the fill valve, and you don't see a white cloud coming out of it, chances are it's just air - but use caution when doing so, and only for a second; keep out of the line of fire when checking.

If you're close to my corner of Ohio, I'd be happy to give you a hand with troubleshooting...

I have 2 valves one black and one light blue with the letter "H" on top, I went ahead and poked the black capped valve and just got a small hiss of air so I assume I have a leak. How would one go about detecting and locating a leak?

Ohh and im in a small city called Norwalk.

Best way to locate leaks is honestly to let the pros do it - they inject a UV dye into the system and then use a black light to locate the leak. Most commonly, the compressor shaft seal leaks - especially if it doesn't get used often; makes the seal dry out over time. But there is a possibility that the leak is somewhere else, so I would be hesitant to just say replace the compressor.

You can buy the dye kit and do it yourself, but it's a bit messy, and you'll likely end up with alien-green dye everywhere.

Norwalk? Small? - Hah! - Belpre's about half the size; and you guys at least have the racetrack (although I missed the last 2 years due to extenuating circumstances). Unfortunately, you're 3-4 hours away, so we'll have to resort to long distance troubleshooting.

Im going to go out on a limb and ask would it be wise to compress the system with an air compressor and attempt to hear a hiss?

Norwalk has a lot of urban development but I still consider it a small city when the tallest building is 6 stories which happens to be the hospital. Guess it's subjective on what a big city is :D

I wouldn't try it myself, all you'll end up doing is introducing moisture into the system, which is a bad thing. The high side of the compressor is going to be close to 200 psi, so chances are your air compressor wouldn't get it up to pressure anyway.

Get yourself one of these:
Interdynamics 436 - UV Leak Detection Service Kit | O'Reilly Auto Parts

along with a can of r134a (should be around 10 bucks), and you'll have all the testing material you need. Like mentioned, just be careful not to spill the stuff, as it will then make it harder to find the leak.

And yeah, subjective is right - we now have a 3 story building with the new medical complex, and they even allowed people to sell alcohol in town (first time since prohibition) a few years ago! I lived in the San Diego area for 10 years - huge culture shock moving to SE Ohio...

Good luck with finding the problem

Thanks for the help and insight, much appreciated!

I have another question, I recharged my system with refrigerant that had dye in it (pretty convenient) but the instructions were vague on the ambient temperature and was curious what ambient temperature did it want the outside temp or the engine bay temp?

The temp outside was 70F (morning) and the temp in the bay after running errands was 90F+ in some areas, I played it by ear and eventually got it cooling again but pressure preset guide based on temp was a bit erroneous since it didn't work the first go.

Those generic kits are generally just looking for ambient outdoor temp, nothing fancy.