Remote Halogen Light Dimmer switch
If like the one we have the light is remote controlled from a small keypad or rotary control.
This operates either wirelessly or wired. The actual dimming is done in the housing where the lamp and fan motor are located. The solid state device that does the dimming has failed. Why? The light that was in the fan....you did replace it didn't you ? probably became a short circuit when the filament failed like tungsten lamps do. This short caused more current in the control device can handle so it became a fuse and failed. This is seldom a user replaceable part. You can obtain a replacement control module.

You'll need the manufacturers name and model number.  Do a web search for Fan Parts. If the site you find listing the fan model included photos find the comparable control be appearance. There is a good chance thats the one you need. You will find the price to be about $40.
If you aren't comfortable with tools or wiring or standing on a ladder ask the dealer to reccomend a repair person.

If the control IS NOT wireless it might be a module mounted the wall switch box and that's a pretty easy fix and less exspensive. Be safe and call an electrician rather than risk fire or electrocution.