Mine didn't flicker last week, it came on and stayed on. I was setting in traffic on my way to work. I noticed my cooling fan hadn't been on in a while. I also noticed last week when I was replacing my drive shaft and yoke on the rear differential that came off, that my over flow tank was full of coolant. I either have a kink in my return hose going back to the radiator of a bad radiator cap not letting the coolant system siphon coolant back in the cooling system... I do know that if the coolant is very low the cooling fan won't come on, just like a car.
If you are loosing coolant out of the motor, check the overflow hose for pinching like you said Bubba, you can remove it from the radiator neck and blow through it to see if you get bubbles in the coolant overflow. I had mine get pinched where it goes between the radiator and frame.
