# 4250 john deere fuel gauge



## farmer dave (Jul 21, 2019)

My 4250 fuel gauge show its full all the time. Is that probably a sending unit problem. How would you guys test this to tell if its sending unit or gauge.

Thanks Dave


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## Tx Jim (Jun 30, 2014)

Remove wire from center post on fuel sending unit & touch end of wire to metal. Does grounding of wire change position of fuel gauge needle?


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## KS John (Aug 6, 2018)

Not a 4250 but you might get some ideas.


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## lagranch (Jul 1, 2019)

With power on, when you disconnect the wire from the sender, the gauge should go to empty and when you ground the wire (touch to metal) it should go back to full. That would indicate the the gauge is ok, the wire is intact between the sender and the gauge, and the sender is bad. If there is no change when you disconnect the wire from the sender, the gauge could still be good and you could have a short to ground in the wire between the sender and the gauge. The next step would be to pull the gauge and disconnect the sender wire at the gauge, again with power on. If you remove the wire at the gauge and it still shows full, the gauge is probably bad. If it goes to empty, the wire is probably shorted somewhere. You can also use an ohm meter to test the sender. As you move the float, the ohm reading should change from 0 (full) to some higher number (empty), but don't be too concerned about the actual number because different senders have different specs. More than likely, your initial suspicion is correct.


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## farmer dave (Jul 21, 2019)

This gives me a really good place to start. Thanks for help.

Thanks Farmer Dave


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