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09 Mariner Fuel Sensor

Howdy everyone!

I recently bought a 2009 Mercury Mariner 4wd Premier from a dealership (I upgraded from a 91 Ford Tempo…)

A few weeks ago I noticed that when I’d start my car the fuel gauge would be wrong (showing 1/4 of a tank when I had 3/4). The last straw happened when the gas light came on although I had more than half a tank. I took the car back to the dealership who verified and repaired the faulty fuel sensor. The mechanic told me it is not a common repair, yet just a couple weeks later I am finding that the problem is happening again.

What are the odds that I got a faulty replacement sensor or could it be a different issue? I will take it back to the dealership once the holiday weekend is over, but I’d like some other opinions. I know replacement parts can fail, but I know it isn’t all that common. Any thoughts or stories about similar instances would be helpful.


I bet it may have not been due to a bad sensor but a contact problem or maybe whatever drives that sensor has an intermittent problem. Him replacing that sensor jiggled the wires and connector around, making it work again. I’d recheck the wires an connector leading to the sensor.

Thank you, I will make sure they do that!

I would verify that the old sending unit was actually replaced, as in "could I see the old sending unit please?? (Too late now)…

Thank you for the information. I just got my car back from the dealership. They re-checked the sender and the instrument panel and ended up tracing the wiring. Come to find out, they’d missed a loose pin connection at the wiring harness. Fortunately the dealership was very helpful and did not charge me for this repair.