What should the voltage be on the gas gauge?
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.
Why is my gas gauge not working at high fuel level?
Some systems are wired so that high fuel level contacts the low-resistance section, gradually increasing resistance as fuel level drops. The system thus outputs higher voltage at high fuel level, gradually dropping voltage as fuel level drops.
How does the resistance of a gas gauge change?
The fuel float contacts run on a potentiometer, or variable resistor, whose resistance changes depending on float level, effecting a change in output voltage. Some systems are wired so that high fuel level contacts the low-resistance section, gradually increasing resistance as fuel level drops.
What are the parts of a gas gauge?
The gas gauge system can be broken down into three basic parts: gauge, sender, and circuit. A fault in one or more of these parts will lead to gas gauge failure. The sending unit is usually part of the Fuel Pump Module : a combination of parts that includes the fuel pump, fuel strainer, fuel filter, and fuel float.
What to do if your gas gauge fails to move?
If the float is OK and the float arm seems to be swinging freely through its full range, replace the tank unit. Ground the gas tank terminal post of the tank sending unit using a jumper wire. If the dash gauge now reeds empty, the gas tank unit is defective. If the dash gauge needle fails t move, the dash gauge is defective.
What causes a bad gas gauge on a Chevy truck?
A poor ground or loose connection to a gas gauge is just as likely to cause problems as loose or dirty battery cables assuredly will with your starting system.
Why does my gas gauge read high when the tank is full?
A functioning sending unit will have a high resistance when the tank is full and a low resistance when the tank is empty. If the gauge reads higher than it should, make sure the wire attached to the electrical terminal on the tank sending unit is making a good ground connection.
Why does my coolant temperature gauge read Cold?
Using your coolant temperature gauge as an example, the diagnostic procedure involves locating and disconnecting the sending unit. With the ignition on, the gauge should register cold. If you connect the sending unit wire to ground, the gauge should switch to read hot. If the gauge moves as expected, then you can suspect a bad sending unit.
