I joined your forum just so I could answer this post.
The fuel light comes on because you are low on fuel. That being said, if you have plenty of fuel in the tank, most likely the sending unit in the fuel tank has a problem.
The fuel gauge is two-fold. A: The gauge itself is activated by a float on the sending unit. B: The light on your dash is activated by a sensor on the end of a heavy wire close to the bottom of the tank. When fuel drops below that sensor, the light comes on. I know this because I just had mine apart and am now looking for a new sending unit. You could try unplugging the sending unit where it bolts into the fuel tank, (on top, right rear from the front of the engine).
By the by, very easy to take out.
Hope this helps.