This one has me going in circles, so I would like to hear how other people handled it. I drive a 2018 GMC Yukon Denali and for about a month the AC has been moody. Some days it is ice cold from the first minute, and other days it blows cool for ten minutes and then just stops, with the fan still running. Once it came back on its own after I stopped for fuel, which made me think it is something electrical and not a real breakdown. My wife says the car is just tired from the summer heat. My neighbor thinks the compressor is on its way out and told me to start saving money. A guy at my gym said it could be a relay or a pressure sensor and that changing parts without testing first is the most common way people waste money. I decided to learn a little before visiting any workshop. One evening I opened a page about GMC cars on a Sharjah website to read how the compressor, the sensors and the control module talk to each other, and it explained that a system can shut itself off when a reading is outside the normal range. That made the on and off behavior make more sense. A colleague then told me to look into before replacing anything, because he says a proper test costs far less than a wrong part. I like that thinking, but I do not know what a real diagnosis should include. So here are my questions. What should a garage actually check first on a Yukon, like gas pressure, the clutch, the fuses or the computer codes? Is it better to bring the car when the AC is not working, so they can see the problem, or does it not matter? Should I ask for the readings and fault codes on paper, so I can compare them with another quote? And how long does a normal AC diagnosis take, and is it usual to pay for it separately from the repair? If you had a similar on and off problem on your Yukon, Tahoe or Sierra, please tell me what the cause was and roughly what you paid. Thanks a lot.
GMC Yukon AC cuts out on and off, how does a proper diagnosis work?
- Thread starter jowanvick
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