It's cold here in Dana Point, I don't even think it ever went above 73 in the past three weeks even in the daytime. Initially, it didn't kick in whenever I had the A/C on, but then it never kicked in, with or without the A/C running, summer, winter, cold start, hot start, 50-mile drives to Los Angeles, it never kicked in. Then it suddenly kicked in after a long 500-mile drive back to Tijuana.
And I never use the thermostat at the auto-level, I always have it either LO or off, usually with A/C off. I had it off driving towards Hermosillo because it wasn't that warm at nighttime and I was trying to maximize my gas mileage, did not want to stop anywhere between Tijuana and Hermosillo. Oddly, it never kicked in after stopping in Hermosillo.