2001 chevy 1500 5.3l 4x4 fuel guage not working. changed sending unit no change. grounded gauge in dash went to full not guage. not getting power to sending unit fuses/ wiring good

Make sure dash guage is working,,," moves when key is turned on,,,,The sending unit in the tank is bad or has came disconnected,,,it will need replaced,,, if it shows full bad sending unit,,, if it shows empty the ground wire is off or damaged,,,,,unless the guage in the dash is bad,,, chevy has had a world of problems with there dashes,,i would think its the dash guage

sender wire grounded somewhere between tank & guage

I'm assuming this has dual tanks, do you know if it is not working on both tanks ?
Most people would check the circuit for the gauge at the tank. The sending unit grounds the gauge on the dash.

If the sending unit was connected and grounded, I would guess the gauge in the cluster is faulty.

When testing a fuel guage you should disconnect the wires to it,guage should read over full,ground the float wire,turn off key then turn back on should read empty.You have to cycle the key for guage to move.If still inop the wire is broken in the harness between the tank and the dash.Voltage on the float wire is low.When tested with a test light it will barely light the light and pulsate.This test indicates the wiring is good.

SOUND LIKE FUEL GAUGE IS FAULTY.IF YOU REPLACED FUEL PUMP ASSEMBLY WITH NEW FUEL LEVEL SENDING UNIT.PROBLEM IS IN THE GAUGES.

well have problems with the voltage regulator on back of the instrument cluster..... no power to the guage it self... if good then check sending unit in tank.. also make sure copper float on sending unit is not full of gas,.. they get pin holes then fill with gas and dont float....because you ground the wire and no change.. i would start with instrument cluster

well its either the wire between the tank and guage in dash or it is the gauge in the dash

i suspect a broken wire between guage and sender unit in tank, but the sending unit could be bad,find the wire to the float guage in the tank and disconnect it, if fuel level does not change then then touch the wire to a ground, if the guage changes then the wire is ok and the unit is bad, if it does not change check wiring and guage for faults.

I had previously replaced the failing fuel pump on my '98 K2500 when it went out entirely. I was ready to replace my 2000 K3500's fuel gauge as it was acting up.
When I started the engine, the gauge would bounce from the middle to way past full then back. It would also jump sporadically while driving on level ground.
I checked the electrical connections at the tank and made sure the frame ground strap located nearby was making good contact. Nothing changed until I removed the instrument panel and cleaned the connections on the back. The fuel gauge seems to be operating correctly now.
There are videos on YouTube that show how to remove the instrument cluster if in doubt. Mine dash has a pop-in plastic bezel followed by 4 screws to hold the cluster in place. It took about a half hour to inspect & clean the dash connection vs. $250 to replace the pump/sending unit combo. Hope this helps.