2002 4x4 chevy duramax low fuel light comes on and fuel gage goes to empty like a direct short?then low fuel light goes off,and fuel gage starts working again?

Check and or test fuel gauge sending unit and the gauge . Videos on youtube showing how to . Also i would have the vehicle checked for DTC's - diagnostic trouble codes . You may want to think about taking to a qualified repair shop .

Fuel Gage
The instrument panel cluster (IPC) displays the fuel level as determined by the engine control module (ECM). The IPC receives a serial data message from the BCM indicating the fuel level percent. The fuel gage defaults to empty if:
• The ECM detects a malfunction in the fuel level sensor circuit.
• The IPC detects a loss of serial data communications with the BCM.
• The BCM detects a loss of serial data communications with the ECM.

DTC P0461
The fuel level sender changes resistance based on fuel level. The powertrain control module (PCM) monitors the signal circuit of the fuel level sender in order to determine fuel level. When the fuel tank is full, the sender resistance is low and the PCM senses a low signal voltage. When the fuel tank is empty, the sender resistance is high and the PCM senses a high signal voltage. The PCM uses the signal circuit of the fuel level sender in order to calculate the total remaining fuel percent in the tank. The PCM sends the fuel level percent via the class 2 serial data circuit to the instrument cluster in order to control the fuel gage. The fuel level information is also used for misfire and evaporative emission (EVAP) diagnostics.

DTC P0462 Fuel Level Sensor Circuit Low Voltage
DTC P0463 Fuel Level Sensor Circuit High Voltage

You need to take it to a shop you have an electrical issue.

why?

I have a 2002 Silverado and it does same thing goes to E low fuel light comes on then it goes back to normal. I was told there is a glitch with that style gage cluster and it has to be replaced. About 500 dollars

fault could be in faulty fuel pump or faulty pcm and short in the ignition switch circuit.

There is no module under the dash on your vehicle .
P0463 - Fuel Level Sensor A Circuit High Description: The powertrain control module (PCM) monitors the fuel level input (FLI) circuit for electrical failure. The test fails when the signal moves above the maximum allowable calibrated parameter for a specified fuel fill percentage in the fuel tank. Possible Causes:

• Fuel pump (FP) module concern
• Incorrectly installed fuel gauge
• Damaged instrument cluster
• FLI shorted to VPWR
• CASE GND circuit open
• Overfilled fuel tank
• Damaged fuel gauge

Diagnostic Aids: See the diagnostic aids for DTC P0460. Application Key On Engine Off Key On Engine Running Continuous Memory Ranger GO to Pinpoint Test HX . All others Refer to the Workshop Manual Section 413-01, Instrument Cluster for fuel level indicator diagnosis.
You start by taking to Dealer or someother qualified repair shop .
Instrument Cluster Diagnostic Trouble Code (DTC) Index DTC Description Source Action B1202 Fuel Sender Circuit Open Instrument Cluster Go To Pinpoint Test B . B1204 Fuel Sender Circuit Short to Ground Instrument Cluster Go To Pinpoint Test B .

Hello: It means to look at the gages, Low oil pressure, high coolant temp, low fuel, low voltage. Basically to get your attention to check the gages.

Jason, as far as the fuel gage, try a couple of resisters at the wiring for fuel gage sending unit, in gas tank. It's two wires, use the resister inline between the two wires. One resister is for low fuel level, the other for high fuel, If the gage reacts properly to both resisters, the problem is the sending unit in the gas tank. You can try 40 ohm and 250 ohm resistors. I used to get resistors from radio shack, I don't know if they went bankrupt? The store in my community closed. Other places may have resisters?
Just to add, the wire colors for sending unit/sensor are purple and black with white tracer.

Is......the problem--"the gas gage reads empty when there is fuel in the tank. OR, The gage moves when the key to turned off ?

If it's the first,
You will need to test the gage and through process of elimination, determin if the Sending unit inside the fuel tank has gone Bad.

If its the second ? - Electrical gauges will move when powered down. Normal

Testing the gauge may not be easy - just depends on your ability.
It is a simple 2-wire gauge circuit, when disconnect (usually need the fuel tank) the gage reads in one direction (either full or empty)
then when shorted-the gage reads in oppisite direction.

Of course you must select the correct wires or you may short out the wrong circuits!! Most GM vehicles use a purple wire & black wire.

A quick method I have used to check the in-take part of the gauge is this.
1st. know there is gas - 1/2 tank works best.
2nd driver's door open, key in run position, engine not running.
3rd gently lift up on the door then let if come back down, gently.
just enough to cause the gas to slosh around.
4th - keep an eye on the gas gage, a bad sending unit in the take will show up as a "twitchy" needle.

Of course, if the gage never leaves empty - sloshing won't work.
I have a known good sending unit I can plug into the vehicle and simulate different levels of fuel - if the gas gage works, I know the problem is in the tank.

Let us know.

Dave

this is a faulty fuel level sensor. it can be replaced seperate from the pump assembly . tank will have to come out to repair