Heated seats are to hot on high setting.

If your seats have the high and low heat settings those are the only control over the temp. The seat has a temperature sensor that if open or shorted will disable the seat heaters all together. If the temp sensor isn't reading the correct current temp of its heater it could allow for overheating which would probably cause it to fail and not work at all. The temp sensor isn't serviced separately from the heating element and would require all of it to be replaced if faulty. Have you tried putting a towel on the seat to dissipate the extra heat?