Fuel gauge not working (not the sending unit)

[BlackMagnum2000]

Hey guys, hoping you can help me out here. Trying to figure out why my dads fuel gauge isn't working.
2006 2500 Cummins. Got a Fass pump on it. Just put a brand new sending unit it in.
When we got the truck, it was intermittent. After pulling the dash out (AC doors), the gauge no longer works at all. I'm thinking it's a wire somewhere, my dad thinks otherwise. Any tips or suggestions will be greatly appreciated

 

[RonJon '06]

Have you done a self test of the instrument cluster? That should tell you if the gauge is functional.

 

[BlackMagnum2000]

Have you done a self test of the instrument cluster? That should tell you if the gauge is functional.

My dad did something, not really sure what. Could you inform me of how to do this? Not as familiar with 3rd gens..

 

[RonJon '06]

Just turn the key to the on position while holding down the odometer reset button. Keep holding down the button until it says "chec" in the odometer then let go. The instrument lights will flash and all the gauges should move to 1/4, 1/2, 3/4 and full. If the gauge moves then like you I'd guess it's on the wiring someplace

 

[BlackMagnum2000]

Yep gauge works.. great. Now to hunt wiring

 

[BlackMagnum2000]

Just to update this thread, which I forgot to do.
If your gauge reads empty, but the sending unit (built into the stock pump) and the gauge are good, then inspect the positive wire. I forget exactly what color.. it can be found on the internet somewhere .. lol. If it reads full all the time, and again both of the others are good, check the negative wire. Both run in the harness under the truck on the drivers side, going through the plug that is directly behind the inner fender well on the drivers front. In my case, we simply unplugged it, put some dialectic grease on it, and plugged it back in, and has worked ever since.

 

[dtomlin]

Old thread revival....
Is there a trick to getting this connection unplugged? Mine is seized together tight.

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