The info that we posted above is for JINMA tractors, and probably don't apply to the DONGFE line different brand, same trouble shooting though. You will need a copy of the electrical drawing. look for incoming power to the gauge it;s self...
You will need a Meter. DMM can be bought for under 20 bucks for a ok one. at just about any tool store. analog ones too, though both are useable I prefer the Digital ones, (DMM = Digital Multi Meter)
One of them should be hot with Key on.
One will be Ground. check resistance to - on battery should be 0 ohmes.
Next remove connector that hooks to sensor, check resistance through the wire to make sure it is hooked up and not broken any where. look for wire colors and or numbering.
use the DC voltage range of 20 volts. start up tractor and check the output of the sensor. should output a spike of voltage, usually avout 3 volts but very quickly. this is where the Analog meter will show up the spike better than a DMM.
You can check that one side to ground if it is 2 wire or wire to wire. if it is one wire, go wire to ground.
try those things and let us know any results.
Mark M /forums/images/graemlins/tongue.gif