2008 Saturn Astra with no AC

Hi people. My fiance’s 2008 Saturn Astra no longer has AC. The compressor does nothing when AC is enabled. You can hear the engine bog slightly when the button is pressed so /SOMETHING/ is happening, but the compressor never budges. My first instinct was to check the freon so I picked up a kit to recharge the system. Pressure was 60psi on the upper and lower ports. Any other suggestions? I saw some people commenting about blower relay’s and resistors. The HAV system and blower work…fine minus AC.

If the compressor doesn’t rotate (which I assume you mean by “never budges”) then your belt would be slipping and overheating. And the compressor needs to be replaced.


Yeah, that’s basically what I mean. However, it never kicks in at all. There’s no squealing like the belt slips or anything, it’s just like the clutch never engages. And when I say the engine bogs slightly, I’m only referring to 100 revs or so…barely noticeable.

The compressor clutch is shot. New compressor.


You can check if the compressor clutch works without starting the engine.

On the electrical connector on the compressor clutch, the black wire is voltage to the clutch and the brown/red wire is the ground. Disconnect the electrical connector from the clutch. Run a jumper wire from the clutch terminal where the black wire connected, to the positive post on the battery. Take another jumper wire and connect it to where brown/red wire connected, and take the other end of that wire and ground it to the engine. If the clutch is good, you’ll see and hear the clutch being pulled in and out each time you ground and unground the clutch.

If the clutch works, then you want to check the clutch fuse in the under hood fuse box. It’s fuse #20/10amp. If the fuse is good, then the problem might with the clutch relay which located in the same fuse box. If the relay is good, then the problem might be with the low pressure switch mounted in the low pressure line.

If all this checks out to be good, then the problem might be with the HVAC control module. And that’s the thing mounted in the dash with all the controls.


Food for thought . . .

The compressor clutch might be good technically, meaning the clutch actually engages when it’s getting power

But if the compressor is frozen/seized . . .

Another possibility is that the compressor is not engaging and what you’re feeling is the cooling fans cycling on which can possibly lead to an RPM hiccup.

If the pressure is 60 PSI on both high and low sides with an inoperative compressor then the system is way undercharged and likely due to a leak. The usual suspect with A/C leaks is the compressor shaft seal. Ideally and at rest, both high and low sides should be in the 120ish range; give or take.