Outside Temp Reading Stuck and Air Conditioner Weak

[Aldo_7]

My '17 Sierra outside temp reading and air conditioner have acted up on 2 different occasions. Few days ago, it was well over 90 degrees but my outside temp reading was stuck at 77 degrees. Also, the air conditioner was very weak, it was blowing cold air but very weak, even though I had it set to max. It wasn't until after about 10 minutes of driving, the temp reading corrected itself and at the same time, the air conditioner kicked in properly. Thought maybe I had pressed a setting somehow on the center console by accident but did not find anything that would cause that. I had washed my truck earlier that morning, hand-dried it completely (even drove it for while after car wash with no issues). It wasn't until after sitting for few hours it starting doing this and by now, I know the truck is fully dried given the sunny weather is over 90 degrees. I find it strange that it has happened twice now. I did read some have experienced the outside temp sensor problems after washing their trucks, (which sounds like GM should fix this issue, I mean, do we have to account for disconnecting our battery every time we wash our trucks, sounds crazy to me) but what's with the air conditioner acting up at the same time? Anyone have same problem?

[O_J_Simpson]

sounds like GM should fix this issue

Did you give GM a chance to fix this issue under warranty?

[Aldo_7]

Did you give GM a chance to fix this issue under warranty?

I have not contacted the dealership yet. I wanted to arm myself with information first prior to going to the dealership in case someone has had similar experience. I'm hoping it's nothing major as I absolutely love this truck..

 

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Yes, it's still under warranty

 

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[TJay74]

I am guessing the AC system relies on the outside temp reading to determine how cold to be, I could see it as part of a fuel mileage savings. I have noticed the same thing on my 2017 Camaro SS in regards to outside temps and the HVAC function.

[likeschevy]

Every time I take my truck through a car wash the outside temp stays stuck on 74 or close to it for at least 20 minutes. It seems 10 or 15 minutes of steady driving and it starts reading again.

[Static]

I am having this same issue. I am going to drop it off for repair soon.

[The Tos]

I have the same issue every time I use the car wash. Kinda weird,

[emeryz28]

If your PCM gets reset, it can take up to 24 hours for the outside temp gauge( the one on the radio screen) to calibrate and become accurate again

[likeschevy]

It is even happening during a heavy rain never happened with my old GMC

[likeschevy]

This is getting crazy mine has stopped resetting you have to ask the question for this amount of money you cant get a outside temp reading to be accurate if you go through a rain storm or a car wash I know a lot of folks have much more serious problems but this begs the question if gm cant make a temp sensor work no wonder they have problems with everything else

[Snoringbear]

I don't think displayed temp, or outside temp for that matter, has anything to do with the ac temp being put out by the unit when the temp dial is on manual. When set on manual (auto light is not on) and the dial is set on Low the unit will produce air as cold as it is capable of producing. However, if the temp dial is set on Auto then whatever the display temp shows to be will be the control number. So, even though there may be a problem with your temp display read out or your Auto feature using your ac on manual it should cool down just fine, assuming there's not another problem....

[Silverado Steve]

This...take it off auto setting and the AC should blow cold. Car wasshing with pressure washing through the grill can affect the temp sensor and as others have said, the temp display controls how the AC works on the auto setting. It will recalibrate after driving over 55 mph for 10 min.

 

 

I don't think displayed temp, or outside temp for that matter, has anything to do with the ac temp being put out by the unit when the temp dial is on manual. When set on manual (auto light is not on) and the dial is set on Low the unit will produce air as cold as it is capable of producing. However, if the temp dial is set on Auto then whatever the display temp shows to be will be the control number. So, even though there may be a problem with your temp display read out or your Auto feature using your ac on manual it should cool down just fine, assuming there's not another problem....

[15 Z71]

Your temp sensor for auto is above the driver seat. Right by the sun visor. That's what adjust the temp on auto setting. I don't think auto has anything to with outside temp.