The low fuel light goes on and off periodically and the fuel gauge fails to work during each episode. what is the cause and the solution .

If the tail lights, low fuel light, temperature gauge, and fuel gauge are not working, there could be several possible causes:

1. Blown Fuses: Check the fuses for the tail lights, low fuel light, temperature gauge, and fuel gauge. If any of these fuses are blown, replace them with a new one.
2. Loose or damaged wiring: Inspect the wiring for the tail lights, low fuel light, temperature gauge, and fuel gauge. Look for any loose connections or damaged wires. Repair or replace any damaged wires and ensure all connections are tight.
3. Faulty sending units: The low fuel light and fuel gauge are connected to the fuel sending unit in the gas tank. The temperature gauge is connected to a temperature sending unit on the engine. Check these sending units for faults, and replace them if necessary.
4. Faulty instrument cluster: The instrument cluster itself could be faulty, causing the temperature and fuel gauges to not work. A qualified mechanic can test the instrument cluster to see if this is the issue.

It's also possible that the trike has a separate electrical system for the tail lights, and that this system is malfunctioning. A qualified mechanic can test the trike's electrical system to determine the cause of the issue.

see if the video helps. Or try disconnecting the battery again for 15 minutes.

https://www.google.com/search?q=2002+Chevy+Tahoe+battery+disconnected+the+fuel+gauge+past+Full+Line

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sounds like someone has had the dash apart. The wiring loom that feeds the speedo quadrant may have come away.

need to replace the sensor

Nine times out of ten, rust in the gas tank has caused the sending unit to rust. WD-40 (large amounts of it), sprayed into the sending unit, usually fixes that.
Also, if I'm not mistaken, the 93 Bronco has a "Low Fuel Light" circuit right next to the gas gauge. If that circuit fails, the gas gauge will also fail.
Start by seeing if you have voltage to the gas gauge circuit with the ignition key on. If you do not, replace or clean the sending unit. If you do, replace the Low Fuel Light circuit plug-in.

The gauge circuit runs through the pump fuse. Most likely the sending unit has failed inside the tank. :-(

could possibly be the fuel sensor sending unit. might have been damaged during the fuel pump replacement.

Hello graytape, was the fuel gauge and low fuel light working and then one day just stopped working?, if so, you have probably blown a fuse and you should be able to locate what fuse and where it's located in the owner's manual.
If you recently got the vehicle and then you found out that the gas gauge and low fuel light doesn't work then that is something completely different.
without knowing the year of the vehicle I can only give you an educated guess.
Many vehicles have a float in the gas tank and this float is directly linked to what you see on the gas gauge. However, after a number of years the floats get saturated from the fuel and become heavy, heavy enough to where they don't float anymore. That is one of the most common causes of the fuel gauge not working.
The sensor that activates the low fuel warning light may be independent of the fuel gauge and the fuel in the tank isn't low enough to turn it on. Your tank has to be very low to activate the low fuel warning light.
Good luck!

The last comment added to thread should work OK.

Could be either a failing gauge or a failing sending unit on the fuel pump. Check out this blog post about a similar problem in Trailblazers - http://drspeedometer.com/chevy-trailblazer-fuel-gauge-quit-working-top-2-reasons-why