Low fuel light not working

[Cloggy Saint]

It hasn't ever worked since I've had the car so when I had the cluster out recently I changed the bulb and it still doesn't come on. What could be the problem?

[PG325]

My low fuel light doesn't come on until the needle is almost under the red section!

Have you run it down really low?

I suppose it could be the fuel sender not sending a signal.

[Cloggy Saint]

It's just before the end of the red section at the moment. I was expecting it to come on as it entered the red.

[Brianmoooore]

Comes on when the needle reaches the bit that actually lights up, not the red painted section.
Only known them fail if the gauge has failed as well - usually as a result of someone trying to remove the fuel pump without removing the sender first.