Question about cars, computers, and heat (please see details inside).

I know that computers hate heat. It’s why we have cooling fans in our laptops and desktops.
But I also know that many of the functions in today’s cars are governed by computers (the transmission control module, for example). It’s also very hot in there under hood, and on some days, it’s hot everywhere, like today in the San Francisco Bay Area where it’s around 100 degrees in the East Bay. How come the computers in cars still work?