heated seats not working
 

I have an ML320 and recently both the driver and passenger seat heaters are not working. The switch light comes on and stays on as usual but the seats do not get warm. The chair pad and back are not getting warm on either seat. I tried to check the fuses but couldn't find one labeled seat heater. Does anyone have any suggestions or have had this issue before? I am trying to avoid going to the dealer as it is not close to my home.