Dear Car Talk: I drive a 2018 Ford Edge. It’s been great. But this past summer, on a 95-degree day where I live in southwest Arkansas, my heater started blasting very hot air. At the same time, the temperature on the car’s screen said it was minus 40 degrees outside. I assure you; it wasn’t.

I couldn’t get it to reset and start running the AC again, despite several attempts that day. The next morning, after doing nothing more to fix it, the AC worked fine.

The next time I was at the dealership, I asked about it, and they didn’t have a good explanation. Do you have any idea what happened? Thanks for your entertaining and informative column. — Carolyn

Informative? We’ll see about that, Carolyn. My guess is that your ambient air temperature sensor went — I think the technical term is — kerflooey.

You have an automatic climate control system. When it’s on — and it’s almost always on, either heating or air conditioning the cabin — you simply set your desired temperature, and the climate control system does the rest.

To do that, it measures the temperature inside the cabin and outside the cabin. If the temperature outside is 95, and you want the temperature inside to be 72, it knows it needs to run the air conditioner on high. And vice versa, If the outside temperature is 45 and you want it to be 72 in the car, it has to blast the heat for a while.

Well, it sounds to me like your outside temperature sensor went rogue. It was not only telling you that it’s — 40 F outside, it was also telling the climate control system that. Not surprisingly, the climate control started blasting the heat.

Why did this happen? Who knows? It could be a one-time fluke. Maybe it’ll never happen again. Or it could be that, like other modern electronic components, these things with printed circuit boards sometimes just fail and need to be replaced.

Once the ambient air temperature sensor went back to normal overnight, everything functioned fine. And it may continue to. But if it happens again, I’d have your shop replace the sensor, Carolyn. It’ll probably cost you around $100 including labor. That’s certainly less than the constant hair care required when it’s 95 degrees out and the heat is blasting.

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