This is kind of an odd one. I drove my 2013 Buick LaCrosse (eAssist Hybrid) to my chiropractor'* office this morning. The Air conditioning was on the 'Eco' mode and functioning normally. When I came out a half hour later and got in the car to go home, the car started normally but the air conditioning did not come on. Sometimes it can be a bit sluggish to begin cooling in the 'Eco' mode so I waited a couple of minutes, but got nothing. Air was blowing out of the vents but it wasn't conditioned. I tried switching to "comfort" mode but it still was blowing warmish air out of the vents. It started getting increasingly stuffy in the car so I opened the windows and the outside air (81 degrees F) was noticeably cooler than inside the car. As I started off from a stop light with the windows down, I noticed a high pitched noise that sounded like a distant siren but quickly realized the pitch was rising and falling with my foot on the accelerator pedal. Since this car is normally extremely quiet, my immediate thought was that something must be seriously wrong, so I shut the air conditioner off and the 'siren' ceased. After about 30 seconds and just for fun, I turned it back on and refrigerated air immediately started pouring out of the vents without the 'siren' sound.

I guess the occasional electronic glitch is part and parcel of having a car with so much technological gadgetry aboard. I've had the touch screen reboot itself a time or two shortly after startup and once the blind spot indicators registered a fault that went away when I restarted the car. I even had a similar phenomenon happen a few times with the climate control system on my 2011 Impala that I had before the LaCrosse. It was a far more rudimentary system and would just remain dark with nothing functioning until I restarted the car. Honestly, sometimes I miss the elegant simplicity of my '68 Volkswagen.

Sounds like the compressor clutch is going out . . . or the guts of the compressor are going out and the clutch is slipping while not able to start the guts turning. Either way, I suggest replacing the compressor immediately so it doesn't contaminate the whole system with metal particles (if the issue is the guts). If it is just a slipping compressor clutch, replace the compressor anyways because the guts are just as old as the clutch and about as worn out.

Hmmmm... That doesn't sound good, especially since the car only has 62,000 miles on it.

Yeah, keep in mind this is my guess based on your description, but there'* nothing else I can think of that comes close to what you've described.

I appreciate your informed analysis and I certainly recognize the limitations of going strictly off of a written description of what happened. I subscribe to the theory that once is an isolated incident, twice is a coincidence and three times establishes a pattern, so I will be monitoring the situation from a more informed perspective.

Is it possible for you to pop the hood and verify where the noise is coming from? Even better if someone can sit in the car turning the a/c button on and off while you listen.

I just got in from driving the car a few miles with the driver'* window open. I turned the A/C off and on several times and could not replicate what happened yesterday. The A/C worked normally, blowing ice cold air with no unusual noises. When I got home, I opened the hood with the idea of just visually inspecting the A/C clutch to see if anything appeared damaged or out of the ordinary and while I know my way around conventional engines fairly well, that hybrid power plant is disorienting to say the least. I couldn't even identify the A/C compressor.

It'* been a week since that little A/C glitch and I've had no recurrences. It'* cooling great in 'Eco' mode in 90-degree heat. I hope I don't jinx it by saying this, but until it malfunctions again, I'm going to put it down to a random electronic gremlin and hope there aren't any repeat performances. I don't see any reason to tear into it right now, especially when I have another car on which the A/C is not working at all.

Yeah makes sense. Weird.

So after more than two months of flawless operation, the air conditioner decided not to come on again. It worked fine when I left out for a Costco run but when I got into the car to head home, it was just blowing hot air. Thankfully, I didn't buy any ice cream. The weird thing was I cut the A/C off and back on a couple of times while I was driving and it would blow a tantalizing puff of cool air before blowing hot again. I let the car sit for an hour and then went out and ran it at idle for about two minutes. Usually, it will start blowing cool air in about 20 or 30 seconds but this time it just kept blowing hot air. I also drove it around the block with the same result. During that little trip, I cycled through the various vent settings—upper, lower, bi-level, outside air, recirculating—but nothing helped.