Answer:There's no switch in the radiator. The low coolant level sensor in the coolant expansion tank is intended to be the sole signal that activates the message at the Vehicle Information Center ...

The next-generation CAP-300 Series coolant level sensor is designed to perform over long periods of time under the most rugged coolant applications. The sensor requires almost no maintenance ...

Parts won't be available to install the coolant-level sensor until later this year. In the meantime, Ford will send letters to owners telling them how to check coolant and add some if it gets low.

I'm not sure what the oil level sensor was, but it was bolted onto the side of the oil pan, so it can't have been terribly complex. Why don't more vehicles have these devices?

In a letter to dealerships concerning a March 2017 recall, Ford says it will also repair any coolant leaks found in some 200,000 vehicles recalled for an increased fire risk.