I own a 2012 TL automatic w/Tech pkg. Waiting at a light on afternoons over 100F, my A/C compressor will disengage until I get moving again and things are good until the next red light. Is this because the system is designed to protect itself from extreme overloading at idle speeds, etc or is a component in need of replacement? I never happens when outside temps are below 100F. Thx for the replies.

 

Hi Rhys Pieces did u ever find out what the issue was with your A/C system?

 

The only thing I have heard concerns the clutch on the a/c compressor. If this is so, it might not be getting quite enough voltage when idling on very hot days. It goes starts working again once the car is in motion. Since heat can impact current flow, it sounds logical to me. I am seeing my mechanic next week and will ask him about it and if the age of the alternator (10 yrs/118,000 miles) is really the culprit.

 

You should get an AC tech to check out your refrigerant levels. This sounds like something from low levels of refrigerant.

 

Took it to my mechanic and he found one leg on the high side pressure sensor was shorting out under the extra heat of stop and go driving in our summers. He patched it and all is well again.