For the life of me, I can't shake the feeling that it won't light up unless it detects reckless driving. It seems like our Niro has only received the message once. Have no idea how it settles on this particular model. It might be picking up on motions on the wheel or something else entirely if it's not detecting eye movements. Or maybe I'm mistaken.
Without a doubt, I concur. In order to help you figure out what's wrong and how to fix it, on-board diagnostics systems are available. They remove all room for uncertainty.
An air bubble can certainly precipitate this problem. Air is a less effective conductor of heat compared to the coolant fluid. Upon the arrival of the air bubble at the sensor, the temperature gauge will indicate a decrease.
Acquire a new display and obtain a CarPlay/MMI box or equivalent; I would advise against a touchscreen, as it poses a safety risk in my opinion. My previous courtesy vehicle featured a touchscreen, which I found somewhat distracting when driving.