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The heated seats use fuse 20 (10A) on the junction block under the steering wheel. The switch lights are driven by an output from the BCM (body control module). But i'm not sure if these lights are working independent of this fuse.
The rear window defogger uses fuse 11 (10A), also on the junction block. Also the defogger relay is switched by the BCM. You could test this relay by putting point 86 from that relay to ground and feel/hear it switching.
Did both problems start at the same time? It could be a fuse of the BCM, there are 3 of them, all on the junction block, fuse 7 (10A), fuse 22 (10A) and fuse 28 (10A).