Replace Your Fuel Tank Sending Unit

Getty Images/Gary Waters

If your gas gauge has been acting boinky, or worse you're running out of gas on a regular basis, you might need to replace your fuel tank sending unit. Sounds bad, but in most cars, it's fairly straightforward to replace a fuel tank sending unit (also known as the fuel sender). Check your repair manual, but if your car has a fuel tank sending unit located under the rear seat or in the rear cargo area, where a large percentage of fuel senders are accessible, you're in luck. It's easy! We'll show you how to replace your fuel tank sending unit with ease.​ 

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Tools You'll Need

Christoph Dexl / EyeEm/Getty Images
  • flathead screwdriver
  • Phillips head screwdriver
  • hammer
  • open end wrenches
  • replacement fuel tank sending unit
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Getting to Your Fuel Tank Sending Unit

Fuel sender access cover removed.
The fuel tank sending unit access cover. photo by Matt Wright, 2007

Before you begin, disconnect the negative battery cable to be sure no electrical sparks are possible. You're dealing with gas which is highly flammable! Also be sure to roll all of your windows down and work in a well-ventilated area. You don't want to be breathing fumes the whole time you're doing this job. Better than this, use a professional respirator to stay fume free! 

Your fuel tank sending unit is located at the top of the fuel tank, but is accessible under your back seat (or under the carpet in your trunk).  The sending unit will be protected by an access cover, usually held on with a couple of screws.

Lift your back seat or trunk carpet and locate the access cover for your fuel tank sending unit. Remove the screws holding the cover in place and remove the access cover to reveal the fuel tank sending unit.

Helpful Hint: Since it's almost impossible to do this job without a single drip of fuel escaping, it's a good idea to have some protection at hand. I like to cover part of my work area inside the car with plastic and an old towel and use this as a staging area for all of my gassy parts. If you hate the smell of gas as much as I do, you don't want to live with it in your vehicle's interior for a week. A little care ahead of time will ensure you don't have a stinky spill to deal with. 

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Removing the Fuel Tank Sending Unit

Removing the fuel tank sending unit.
Remove the fuel tank sending unit. photo by Matt Wright, 2007

Another Safety Note: Gasoline is highly flammable. By removing the fuel tank sending unit, you are opening the gas tank. Be sure there are no sources of spark or flame nearby. Always do this repair outside with the windows of your vehicle rolled down. Never open your tank in a garage that could have a source of ignition like a furnace or water heater. 

With the access cover removed, you'll see the fuel tank sending unit right there on top. It will have a wiring harness plugged into the top (this tells your gas gauge how much fuel is in the tank).

Unplug the wiring harness and move it safely to the side. If your fuel tank sending unit is screwed or bolted in place, remove the screws or bolts.

Some sending units are a "twist-lock" type. They work like the old twist-lock gas caps. You'll see a few notches along the outer ring of the sending unit. Place the tip of a sturdy flat head screwdriver in the notch and gently tap it counter-clockwise. The sending unit will rotate until it's loose. (the picture above shows the fuel tank out of the car to illustrate the fuel tank sending unit's location).

Now you can remove the fuel tank sending unit in one piece. Attached to it is a long rod with a float at the end, so you might have to try a couple of different angles to get it out.

As usual, installation is the reverse of removal. Don't forget to plug the new sender in or it won't send you anything! If your fuel filter is in the tank at this location, be sure to replace it, too. If not, follow these instructions