I'm a heavy driver and have about 85k miles. About 2 months ago (November 2018ish), my coolant light came on. I topped it off and about a week later it came back on again. I went to dealer and they topped it off and I took it in for a pressure test a week later. So they determined NO LEAKS and topped the coolant off again. Yesterday the temperature dropped to almost 10 degrees . when I got in my car to leave work, the coolant light was back! Is it possible that the sensor is just wacky when it's super cold outside?? Although I am a heavy driver, I keep up with maintenance regularly and in the 4 years that I have had this truck, my coolant light has never come on until November. Any idea what the issue could be? I hate spending money at the dealer just to get a diagnosis of nothing.