John Deere 285 coolant sensor, FD590-V Kawasaki motor

[JEDOUGLAS]

Hi all,
I have a 1989 John Deere 285 lawn tractor with the Kawasaki FD590-V motor. Recently, my coolant temperature light came on and has remained on since - as soon as I start up the motor. I've changed the oil, filters, checked cooling fin screens, replaced fuses. What would be the next move to get to the bottom of this? Coolant temp sensor, thermostat? I'm no mechanic, so anybody with an idea of where to look next would be greatly appreciated. Also, it doesn't appear to be running any different. I'm thinking it probably isn't running hot but I don't want to risk it
Thanks,
Jon

 

[Zebrafive]

Since the coolant temp light comes on at start up. Thermostat would not be a problem. It is either the sensor or the wiring to it has shorted to ground or shorted to another wire if wiring is rubbed bare or chewed by mice etc.