I replaced my seat heater element a couple of months ago. You will need to take the seat out, remove the leather seat cover and it will be obvious where the break in the element is. Most likely it is under one of the folds in the seat. Bought a heater element on ebay and it worked great.
You MUST have a hog ring pliers and a bunch of hog rings to put this all back together. Found these at my local hardware store and it was under $20 for both. Don't even think about doing this without the hog ring pliers and a supply of new hog rings. Total time was about 3 hours.