Engine coolant overtemp

So I’ve seen some posts and theories on “Engine Coolant Overtemp” and why this light is coming on and then turning off, like thermostat or radiator cap issues, but I’ve had this condition happening for three years now. I assure you that I haven’t lost one drop of water and have driven from Houston to Tucson three times with the light on my dashboard coming on then turning off after 3-5 seconds. If it would have been either of those or a water pump or hose I would have blown water out immediately. Recently it has started to come on more often and now the AC cuts off when the warning comes on, then back to normal and ac works again after 3-5 seconds. Does anyone have any ideas of what sensor it might be? The dealer wants $180 to tell me what sensor it is, or what it isn’t.

 

Welcome from LA (Lower Alabama)! I would post that question in the Ask The Toyota Mechanic thread. Those guys can help you out.
https://www.tundras.com/threads/ask-the-toyota-mechanic.2404/

 

Welcome from NY.

 

Welcome from Pennsylvania