How do you test your fuel gauge and sending unit?
Test between the positive terminal on the fuel gauge and a good ground; the reading should be 12 volts. If it isn’t, check the ignition circuit. If that reads 12 volts, turn off the ignition. Then use the Ohm scale on your multimeter to check continuity between the ground terminal on the gauge and ground; the reading should be at or near zero Ohms.
What do I do if my gas gauge is not working?
In most cases, to gain access to the fuel tank sending unit mount / fuel pump mounting hole, you’ll need to drop the gas tank down. Be sure to do this when there is either minimal gas in the vehicle, or it’s been siphoned out.
What happens when fuel gauge reading is zero?
If the reading in Ohms is zero or close to zero, your sender has a problem, but there is a proper completion of your circuit. For a fuel gauge to complete and function thoroughly, the resistance in the sender’s rheostat needs to match the gauge. First, ground wire from the contact stud to the chassis.
How do you remove a fuel gauge from a tank?
Remove the screws that hold the sending unit to the tank and take it out. Next, remove the three wires on the back of the old gauge. One wire goes to the center pin on the tank sending unit, one goes to ground, and the third connects to a 12-volt source, normally the ignition switch. Remove the fuel gauge.
Test between the positive terminal on the fuel gauge and a good ground; the reading should be 12 volts. If it isn’t, check the ignition circuit. If that reads 12 volts, turn off the ignition. Then use the Ohm scale on your multimeter to check continuity between the ground terminal on the gauge and ground; the reading should be at or near zero Ohms.
What does it mean when your fuel gauge is wrong?
Some owners may see an erratic or unresponsive fuel gauge or a fuel gauge that does not reach the full level after filling the fuel tank. Plus, some vehicles may display a check engine light on with the following trouble codes:
Why does my car have a check engine light on?
The exact resistance the computer expects varies with year, make, model and whether the fuel gage is analog or digital. Some owners may see an erratic or unresponsive fuel gauge or a fuel gauge that does not reach the full level after filling the fuel tank. Plus, some vehicles may display a check engine light on with the following trouble codes:
What should the voltage be on the gas gauge?
Remove the fuel pump module so you can manipulate the float arm. At this point, with the key in the ON position (but without starting the engine), back-probe the connector and check for voltage. You should always have 5 V or 12 V on one of the pins. One of the other pins will be voltage feedback to the gas gauge.
What kind of resistance does a fuel gauge have?
Several companies provide pre-packaged “ready-to-go” installation kits. Most sensors have a mechanical floating arm and a rheostat. When the arm is all the way down, in the “empty” position, the resistance in the circuit to the gauge is near zero. As the arm rises, resistance in the circuit also rises to around 200 Ohms.
Why does my fuel gauge need to be replaced?
Another common problem results when the rheostat doesn’t transmit the correct electrical current to the fuel gauge, even though the floating arm is moving up and down properly. In this case, both the sender and the gauge need to be replaced. Left: My new sending unit installed.
Several companies provide pre-packaged “ready-to-go” installation kits. Most sensors have a mechanical floating arm and a rheostat. When the arm is all the way down, in the “empty” position, the resistance in the circuit to the gauge is near zero. As the arm rises, resistance in the circuit also rises to around 200 Ohms.
Another common problem results when the rheostat doesn’t transmit the correct electrical current to the fuel gauge, even though the floating arm is moving up and down properly. In this case, both the sender and the gauge need to be replaced. Left: My new sending unit installed.