RE: heated seats
The wires that heat the heated seats are very thin (think wires inside a toaster) and more than likely, someone has "knee-d" the seats and broken one. When one is split (i.e. broken) the rest will not work and the circuit is broken. In other words, someone has leaned into the car. putting their knee on the seat followed by all their weight, on that sole knee and that has broken a wire. Not a small job to fix. The light illuminates because the sweitch is still good.