bruno your lucky if your seat heaters are really good, i have had 2 IS300h's and neither of
them had good seat heaters the CT i had could cook you they where so hot.
i know this isn't in your original post but if the heaters go to the next lower heat setting too
quickly for you if you press and hold both heating buttons at the same time you will hear a beep
confirming the timer has been turned off the heater will then stay on the setting you have
set the seat at.