This page here has an answer regarding why the fan light may not be working. It goes on to talk about wiring colors etc. so you may need to open up your fan and take a look inside. Hopefully this information is helpful.
Note: Always make sure to cut the power off at the breaker before taking a look inside the canopy or housing. You can’t look at wires while they’re still hot, so make sure the power is switched off at the breaker (or fuse panel).