My mom has a ceiling fan with a light kit. When the wall switch (single
toggle) is in the on (up) position the fan will run and when the switch
is in the off position (down) the fan stops running. OK, that is normal.

Here is the problem, the light will only turn on and off using the
chain, and it doesn't matter if the wall switch is in the on or off
position. Wall switch up, light turns on and off with chain. Wall switch
down, light turns on and off with chain. What is going on here?

BTW, this isn't a new problem. She bought the house 6 years ago and it
has just now been brought to my attention.