Join Date: Jan 2011
Car: 2006 Outback XT Limited
Feedback Score: 0 reviews
It's very likely the heater element itself. They do wear out, mostly from flexing around inside the seat cushion. It's a relatively dumb system, the only protection built in is the fuse. When the heater element gets particularly bad, it will draw too much electricity and blow the fuse. Yours sounds like it is well on the way to this.
The bad news is that you'll need to take the seat apart to replace the element. It might wind up being easier to hit a junkyard for a used seat.