Recently bought a bobcat 442 (made by terex). As soon as you crank it the gauge goes straight to max temp and the overheat light comes on even if the machine has been sitting for days. I figured it was the coolant sensor ( this year model is liquid cooled not oil cooled) so I changed it but that didn't help. The only thing I can think of now is that the gauge is bad. You can't just replace the gauge you have to replace the whole display so I am sure that is not going to be cheap. Any other ideas as to the cause. I would hate to buy a display and then that not fix it either.
What happens if you just disconnect sensor?
I would try running a test wire from the sensor to the gage to eliminate the possibility of a break or short before changing the display