Hello there.
We drive a 2011 GLK 350. A bit over 100K miles.
Suddenly the A/C came with a weird issue: if the car is parked in overnight, in the morning we turn the A/C on and it works as it should.
But after spending 8 to 9 hours in my workplace parking lot under the scorching SoCal heat, when we turn the A/C on, only hot air comes out of it. After 10, 20 and even 30 mins only hot air comes out. No sign of cold air at all. It feels like forced hot air is coming as it would with the heat set to max when it is not.
But when we turn the temperature control from max cold to the center and then back to max cold, then the A/C kicks in and works as normal. This happens on both sides of the control panel. Either the Driver or passenger control, when changed then the A/C starts to work as it should.
My theory is that there is some sensor or relay that because of the heat dilates and gets stuck until the temperature control gets changed and that change releases said sensor/relay so it starts to operate normally.
The car has been diagnosed with no issues at all at two indy repair shops, freon level is correct, compressor works fine and as I mentioned the issue only happens after the car has been sitting outside at very high temperatures.
Does my theory make sense? And if so which sensor/relay could it be so I can try to replace it?
Thank you in advance.