2nd Gen Non-Engine/Transmission fuel sending unit?

[RHoblitt]

My fuel gauge on my 98 3500 started going from full to half tank in 100 miles or less so i bought a new sending unit and ran the tank almost dry and droped it and installed a new sending unit and now my gauge only moves a little past the red empty mark towards full when i refilled it. Any ideas what might be wrong here. I was very careful when removing and replaceing the new one. Thanks
Richard

 

[illflem]

Short the wires at the module to ground one at a time, one is a ground and won't do anything, another will make the gauge read full, the last will make the low fuel warning light come on. If you don't get these results the problem is between the module and gauge. I'm thinking you have a bent terminal at the module connector or a broken/loose wire at the same location.

 

[RHoblitt]

Thanks i will check that. One of the wires on the sending unit was loose on the spade so i crimped it a little but all else seemed ok. Will get out my test equipment.
Richard