Has anyone had the issue of the fuel guage for 2010 2500 Ram diesel gone haywire? Reads 3/4 one moment, empty the next, full, 1/4 and so on. My guess is the fuel sending unit. Wondering if there so some other sensor?

 

BigRedAZ,

I'm sorry to hear about the inconsistency with your fuel gauge. It is possible an issue has occurred with the fuel level sensor. Are there any stored fault codes?

 

If you can get at the wiring going to that gauge, you should find 3 wires (or 2 wires if the case is grounded to the mounting in some way). These wires will be Signal, +12, and ground. Using a multimeter, you can see if the power (+12) or the Signal is fluctuating. Once you know this, you'll have a better idea of where the fault lies.

 

I did not get any fault codes. I will try Alfons suggestion next as soon as I can. I noticed this morning when I hit a bump it went back down to empty. These old dirt roads are tough on vehicles. I am hoping its not the sensor but most likely will be. arrg!

 

BigRedAZ,

Keep us posted on the results if you can.

 

There's a sticky on this forum that has a link to wiring diagrams - they should be helpful.

The symptom you describe in your last post (gauge reading empty and no "Low Fuel" indication) would lead me to strongly suspect the gauge or the wiring to the gauge. If the sensor was sending the signal voltage for empty, you should have seen a "low fuel" indication on your instrument panel. If the power (could be the +12 or ground or both) to the gauge is OFF, it will read zero and the computer won't know any difference and won't give you any instrument panel indication.

Good Luck.

 

Your first post said that it could also flick to FULL, this is a symptom of NO SENSOR SIGNAL while a reading of zero is a symptom of NO POWER - both can be affected by a bad ground or loose connector/connection to the gauge. The way the gauge usually works is that power will drive the needle to the full side and the sensor signal provides the bias to position the gauge at the correct position

 

Try the cluster self test to eliminate the gauge itself.

SELF TEST

The instrument cluster self test will put the instrument cluster into its self-diagnostic mode. In this mode the instrument cluster can perform a self-diagnostic test that will confirm that the instrument cluster circuitry, the gauges, and the indicators are capable of operating as designed. During the self test the instrument cluster circuitry will position each of the gauge needles at various calibration points, illuminate all of the segments or portions in the Liquid Crystal Display (LCD) unit, and turn all of the indicators ON and OFF again.
Successful completion of the self test will confirm that the instrument cluster is operational. However, there may still be a problem with the CAN data bus, the Powertrain Control Module (PCM), the Totally Integrated Power Module (TIPM), the Transmission Control Module (TCM), the Occupant Restraint Controller (ORC), the Controller Anti-lock Brake (CAB), the Wireless Ignition Node (WIN) or the hardwired inputs to one of these electronic control modules. Use a diagnostic scan tool to diagnose these components. Refer to the appropriate diagnostic information.
1.
Begin the test with the ignition switch in the OFF position.

2.
Depress the odometer/trip odometer switch button.

3.
While still holding the odometer/trip odometer switch button depressed, turn the ignition switch to the ON position, but do not start the engine.

4.
Release the odometer/trip odometer switch button.

5.
The instrument cluster will simultaneously begin to illuminate all of the operational segments in the LCD unit and perform a bulb check of each operational Light Emitting Diode (LED) indicator. The LCD segments and LED indicators remain illuminated as each gauge needle is swept to several calibration points and back. If a VFD segment or an LED indicator fails to illuminate, or if a gauge needle fails to sweep through the calibration points and back during this test, the instrument cluster must be replaced.

6.
The self test is now completed. The instrument cluster will automatically exit the self-diagnostic mode and return to normal operation at the completion of the test. The self test will be aborted if the ignition switch is turned to the OFF position, or if a vehicle speed message indicating that the vehicle is moving is received from the PCM over the CAN data bus during the test.

7.
Go back to Step #1to repeat the test, if necessary.

 

That's good info Pedro. I've certainly learned something from that, I didn't know about the self test capability & also didn't realize the whole cluster was one "lump" in terms of serviceability.