Fuel gauge will not register

Hi and thanks for using 2CarPros. Com.

Most times, the level sensor rheostat goes bad. However, a bad ground can do the same thing. First, and I hate to say it, but the fuel tank needs removed to access the fuel sending unit. The fuel level sensor is part of the fuel pump, so that is where we have to go.

First, I attached a picture of a wiring connector plug that will be to the pump assembly. Confirm that there is both power and ground at this plug. Look at picture one below so you know what pins to check for ground. Confirm there is continuity between pin 1 and ground. Note that continuity in and of itself can provide a false positive result when using a multi-meter. Even if it shows continuity, the source may be too weak to handle a load. I use a back up light socket and bulb and use the provided ground and supply power to the other side of the bulb. If it lights up, great. If it does not or is weak, suspect a weak or bad ground.

If the ground is good, either the body control module is bad or the rheostat is bad on the level sensor. To confirm the rheostat is good, you will need to check ohms. Picture 2 shows what ohms should read based on the amount of fuel in the tank.

If the ohms are off or do not meet the manufacturer's specs in picture 2, replace the pump. If the ground is good and the sensor tests good, suspect a faulty BCM. Picture 3 is of the pump itself and shows the location of the sensor in question.

If you have other questions, feel free to ask.

Take care,
Joe