I cannot find any manuals for a L3000 tractor on Kubotabooks.com.
Tractor data says the preceding model was a L2600 and the next year a L4300.
The last place I looked was on this WSM download site.
http://kubota.servicemanualvault.com/index.html#l-series
Their manuals are around $10 and can be an excellent resource for troubleshooting.
However, again there is no L3000 listed.
Perhaps you know that the L3010 is the same tractor as a L3000. I do not.
Plse look on kubotabooks.com and see if you can find a manual that would be representative of your tractor.
It is not always true that something like a temp sensor wire will show battery voltage.
If your dash shows a scale for temp and not just an idiot light that turns on, then there are electronics involved and voltage signal to the sensor will in all probability not be battery voltage. The instruments cannot work with the fluctuating voltage from the alternator charging the battery.
Since I don't know your specific tractor, I need some reference material to study in order to suggest what may be wrong.
Always a good starting point is to locate and then remove and clean the ground connection for the instrument panel. Not just a visual inspection.
Dave
