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Hi, you will need to ohm out the individual sending units to see which one is open. I have never had any luck cleaning them. Usually they aren't dirty but the circuit board wears out and there is no contact. Click here for the instructions to remove the sending units.
Hi! Just got your answer...looking at the diagram, you have to access the fuel sending units from the outside of the car, underneath?
That is correct
does the tank have to be empty??
Yes, or nearly empty.
oh boy...that's hard to know considering the gauge doesn't work! Any special tools needed?
The tool to remove them is listed at the bottom of the document.
ah yes, sounds pretty straight forward...jack up car, remove from underneath. How do you ohm it out? What are the readings? 0 ohms for full? And around 300 ohms for empty? That's what I see in the forums...
I would mainly be looking for an open circuit. Just measure across the two contacts and move the arm of the sender up and down. You can also ohm them out in place when the gauge is not working. Just disconnect each sensor and see which one does not give you a reading.