From Heatedseatkits.com:

"Hello,

Yes, we have alot of customers who own the same car as you with the same
problem. You can replace your current defective seat heater element with
ours because your current elements are made of copper and can easily break
down (if any point of the copper wire breaks, the entire seat heater element
will not longer work). Our seat heater elements are made of carbon fiber so
it doesn't matter if one wire breaks or twenty wires break, it will still
work. Bascially our elements work the same way as an electric stove top
element. When you add positive and negative, it will product heat. You will
need to purchase H3 seat heater kit (the most ideal kit for your solution).
Our solution is much cheaper because it will last longer and you don't need
to buy the cloth/leather seat cover that the dealer forces you to buy also.

Best Regards,
HeatedSeatKits.com"

Thanks for the input