I Fixed MIne
My heated seat failed and I found that the wires had broken inside the seat itself. here's what I did:
Carefully removed all the staples holding the seat cover to the seat pan.
Removed the cover and foam together from the pan (No need to separate the cover from the foam)
Dug into the foam until the found where the wires were broken...in my case, it was in the forward area, just where my body weight rested.
Using a Dremel tool, I hollowed out the foam around the broken wires in order to allow room to solder the wires back together) To allow access without destroying too much of the foam, I cut out a couple of large block shaped sections of foam .
I soldered the broken wires, and covered each wire with heat shrink to give a little more strength.
I filled up the cavity around the repaired wires and glued back the large pieces of foam using silicon adhesive.
Since I didn't have the right stapler, I took the seat to an auto upholstery shop to re-attach the cover and foam. (Cost $65....yipes!)
This all happened recently, but I've since put about 1500 miles on the seat and it works fine. I'm worried however, that there is an inherent failure mode where your weight rests on the wires. I had about 30,000 on miles when it broke. I weigh 170 lbs
Let me know if I can provide any more info.