strange AC Issue Please Help

[Dmo3uae]

hello

I have strange problem in my 2011 Yukon Denali.
the car had fault cooling fan that was replaced. but when I got the car from workshop it had strange thing in ac unit
the outside Temp is also appearing in the AC controller ( Workshop said that he didn't flash the car)




My Problem:
After 1 week the AC compressor refused to start at all (Even checked by workshop)(AC light is on but its not working). the only way to make it work is to disconnect the car battery for a while (1 hour) then connect it back. by doing this the compressor will work for one or 2 days then it stops again. did anyone face this problem before??

Also as you can see in the images (after disconnecting the battery) that the outside temp is 55F but this is WRONG. the real temp was 100F and it only corrects (goes up slowly) if you start driving the car and stays in correct range until you disconnect the battery again.

please help me if you know the solution.

 

[Dmo3uae]

please help me

 

[Mikana31]

I have heard the outside temp sensor can go bad and effect the AC. They're no very expensive, but a bit hard to get to.

 

[swathdiver]

hello

I have strange problem in my 2011 Yukon Denali.
the car had fault cooling fan that was replaced. but when I got the car from workshop it had strange thing in ac unit
the outside Temp is also appearing in the AC controller ( Workshop said that he didn't flash the car)
View attachment 348975

View attachment 348987

My Problem:
After 1 week the AC compressor refused to start at all (Even checked by workshop)(AC light is on but its not working). the only way to make it work is to disconnect the car battery for a while (1 hour) then connect it back. by doing this the compressor will work for one or 2 days then it stops again. did anyone face this problem before??

Also as you can see in the images (after disconnecting the battery) that the outside temp is 55F but this is WRONG. the real temp was 100F and it only corrects (goes up slowly) if you start driving the car and stays in correct range until you disconnect the battery again.

please help me if you know the solution.

You really need to put a Tech-2 on it and pull all the internal codes. If the temperature sensor went bad, you have to pull the bumper cover to get at it, or at least loosen it so get in there. But as for the numbers showing up when they were not there before, doesn't sound right to me either. @Doubeleive has more experience with these modules doing funny things than I do.

 

[Doubeleive]

the sensor is behind the grill, you can pull just the grill portion to change it if you need to, the outside temp showing up on the ac control is a option but from what I understand it has to be done with a tech2, mine was displaying it but had the wrong calibration and when they updated it the outside tempt was not showing on it anymore. I haven't messed with mine to see if I can make it appear again. But it sounds like your issue is the ambient temp sensor, pretty simple to replace it just get one from the dealer parts department and it's plug-n-play

 

[Dmo3uae]

@Doubeleive
Thank you for your reply
the sensor was changed but it didnt fix the main problem
My problem is that AC compressor stops working and the only solution to make it work is to disconnect the battery for several hours

 

[Doubeleive]

@Doubeleive
Thank you for your reply
the sensor was changed but it didnt fix the main problem
My problem is that AC compressor stops working and the only solution to make it work is to disconnect the battery for several hours

you failed to mention this, and if it still requires you to disconnect the battery then either the new sensor is bad or you have a short in the harness somewhere, obviously the ac pump and fans. etc work properly when it has the correct temperature reading so that narrows it down to the sensor or sensor harness or a bad ground.

 

[Brandon2489]

Does it do this in auto or manual mode?

 

[a4edwin]

Didn’t know outside temp showed up in those two places. Mine is only in the rear view mirror.

 

[alpha_omega]

If the ac compressor is stopping, that is usually a sign of low oil in the compressor. As a “fail safe” they turn off if their isn’t enough oil or if the pressures are incorrect (i.e. low Freon).
If the a/c was just topped off and the pressures were not correctly checked (high side and low side) with a vac and a set of gauges, then you will want to start there. Hard to tell for sure without a Tech2 hooked up.