To troubleshoot this, you'll need to consult your owner's manual's electrical diagrams. These diagrams will show the various circuits related to power seats and the associated fuses. You'll likely find several fuses involved in the power seats' operation, and you'll need to check them all using a test light or multimeter. They are typically located in the under-hood fuse box and the interior fuse panel (usually under the dash).
In short: There isn't one single "power seat fuse." You need to consult your owner's manual's wiring diagrams for a systematic approach to diagnosing the problem.
