It's been pointed out by other members, but it seems your assumption is wrong.
You want to heat an empty seat? They remove it because it's not needed without anyone sitting in the seat. At this point you can't place another button there.
It took me a while (which it shouldn’t because those things should be intuitive) but I finally got the (twisted) logic. The passenger seat warmer shows up only if you have a passenger _and_ you have the split HVAC enabled _and_ you have a driver. Why the seat warmers must be related to the HVAC settings is a mystery to me. Why the passenger icon shows up only if there is a driver _and_ passenger is also a mystery.
Now, in order to see the status of both seat warmers I must enable the split HVAC and play with two temperature settings instead of one. And to make things even more interesting the passenger seat warmer icon disappears when there is no passenger but the heating is not turned off.
In summary, the only way this works is if:
- There is a passenger _and_ driver in the seats
- The split HVAC is enabled.
Common cases when one will have issues:
- You want a single HVAC settings
- Forgot to turn off the passenger seat warmer _before_ the passenger leaves
- The passenger is waiting for the driver in the car. This is particularly ugly because you cannot expect common people to be able to find the twisted HVAC logic.
Those UI engineers have never driven a car before, that is for sure! Why something so simple, that has been solved eons ago, has to be so complicated?!