When you hit the heater switch and the light comes, do you hear a click sound from under the seat just before the light goes back out?
If so, you probably have a bad element in the seat.
It can be fixed, but finding the bad element can be tricky, since there are several elements in the seat that can go bad. Once you find the bad element, you have to partially remove the seat cover to access the elements.
Mine is bad, but I don't use the seat heater, so I have not attempted the fix. I hear it is not very easy.
O'Neil - I got the heater element kit from the dealer today but it is a little different from the above image you posted. Sure it looks the same as the picture but in reality there are more connectors than shown. Can't get a good pic of under the seat to expain what I mean but the bottom cover has three green connectors and the back element has one plus the large connector.
It seems that the original elements really are part of the leather upholstery and the wiring is different as you can see in the picture of the kit elements.
What did you do with the original elements?
How do you connect the bottom elements without replacing the back?