Is there a fuse for the heated seats in the tl? Drivers side works, but not the passenger side.

 

Make sure it's not just a burned-out light on the switch, which seems to burn out for quite a few members. Have a passenger turn on the heater for a trip to see if the seat heater works.
If it's the switch's light bulb, there are multiple thread on pulling up the console trim and moving the cupholder to access the switches.

Otherwise, if the seat heater doesn't work, is anything else broken? Fuses usually are connected to multiple devices on the TL, like the driver's seat motors are on the same fuse as the mirrors and windshield spray motor, for example.

 

both heaters run off the same fuse. Most likely the heating element has gone bad on the passenger seat. very common issue