[WhoCares]

Hi there everyone I have a couple questions I hope someone could answer.

1 Does the heater use the AC for any function?
2 Will the AC function in cold temps?

I live in Iowa and it’s getting colder. When I got in the car this past Sunday I clicked the Auto button for the climate control. This is the main switch I use. When it came on I noticed that the air condition light was also on even though I had the heat set at 90 to warm the car. The heater seemed to work fine even though it said AC. I thought this strange so I hit the AC button and turned it off. The outside temp was upper 30’s. Today I get in the car and hit the auto button and noticed the AC light blinked three times and went out. Touching the ac button again gave the same outcome. Outside temp was 32 and dropped to 28 during my drive. The heat seems to work fine. When switching to defrost it continues to blow hot air. I did not try switching to vent or floor as I was preoccupied with the importance of my trip.

My wife is the daily driver of the Buick and I swear every time I get in it I notice some new issue. It’s funny yet not as our warranty is long expired. We’ve never had a problem with heat or AC. Was the light flashing because it was too cold for the AC function? Should I be worried about an issue arising? Is this a possible blend door issue? Any info or advice is greatly appreciated.

 

[kevcol1974]

It all depends on the setting "Auto" gave you, but generally the AC doesn't work in Auto in the cold. With front "Defrost" on, the AC should "kick in", though the cold air isn't coming into the cabin. Manufacturers do this to engage the AC compressor and decrease the chance it seizes over the winter months from not being used. The AC light coming on with "Defrost" is normal.
However, the situation you are describing sounds like what mine is currently doing. Temps dropped, and I turned my AC off manually one day. A few days later, it warmed up (typical weather for Southern Ontario) so I wanted the AC back on.... hit the button, it flashes at me, then goes out. I suspect my freon is low, but have yet to look into it, as the snow is flying here today. Part of me wants to wait until spring, another wants to take care of it now, so the AC Compressor doesn't seize.
Regardless of outside temp, you should be able to manually engage the AC to blow cold air, unless there is a problem with the AC system. (low freon, AC compressor issue, switch or fuse issue)

 

[Emmen]

If you haven't replaced the rear evap coil then it could be the manufacturing defect in it. There is a TSB on it. Mine went at 37,000

 

[JayS]

The flashing light is exactly what it's supposed to do when you try and turn the AC on and it's cold. It even spells it out in the manual. The system is protecting the compressor because it's not good to run it when it's cold. This happens any time the air temp sensor hits 40 or below. It had me worried because the 3x flash is also the same exact error you get when the AC system has a critical fault, like low pressure from a leak. To be sure when it first happened I fired up the heater in the garage and got it up to about 60 and sure enough the AC would engage just fine.

I found it odd when I first got mine as well because every other modern vehicle I've owned has automatically turned on the AC when choosing defrost since AC works as a dehumidifier and greatly helps with defrost.

 

[WhoCares]

We don’t have a heated garage to warm the Buick up. Right now it’s 24 and feels like 14. Saturday is supposed to be the warmest day we’ll have in weeks...possibly until spring. If it gets that warm I will check to see if the AC will engage on its own. Until then I’ll do more research on the rear evaporate coil. Thanks for the replies guys!

 

[Emmen]

Search here and you can find lots of info on the AC problems

 

[WhoCares]

So today it’s in the mid 40’s and I had time to take the Buick out for a drive. Right after starting the car I hit the auto button on climate control like normal with the temp set to 90. The AC light came on and stayed on in auto mode. I cycled through all blend configurations (defrost, floor, combo vent etc) and had heat in them all. Then I then turned the temp all the way down to 60 and could feel the cold air change over quickly. I then went through the rear controls as well.

To recreate the issue is had I manually turned off the AC and then back on. Light came back on and stayed lit. Everything seems to be working just fine now. I’m wondering if it was so cold the other day it was in a safe mode and that’s why I couldn’t manually turn it on. The wife hasn’t had any issues at all this week so ?? everything’s ok

 

[JayS]

Like I said, it’s doing exactly what it says it will do in the manual. It’s fine. It is a little unnerving that it flashes the exact same way as if somewhere were broken and you’re left guessing if it’s just below temp or broken. Would have been a much smarter engineering decision to just turn the light on as if it was on and simply not turn the compressor on. Save the bringing error light for when here is actually a problem.