Before checking the fuse, run the seat all the way forward and as high as it can go. From the back seat floor, look at the seat module and wiring. If you see any burned connectors or bare wires, you'll need to resolve those issues first.
If everything looks good, replace the fuse and see if the problem persists. If it doesn't, then you'll probably need to replace the heating/cooling module. First be sure to check the functionality of the switch, using a voltmeter at the seat plug, unplugged from the unit, with a good fuse in place.
If you use the exit back function when shutting off the car, you more than likely have a bare wire from rubbing as the seat goes back and forth. OEM wiring under the seat was not secured properly to prevent this from happening over the long run while using this function.
Have a good day.