Control panel for a Heller heater unit. Top row has an On/Off switch followed by four LEDs: Cool Air, 1000W, 2000W and Swing. Pressing the On/Off switch cycles through those four modes, although the Cool Air LED will remain lit when the device is in 1000W, 2000W or Swing mode. You can't actually turn the heater off. You have to put it in Cool Air mode and it'll turn itself off after 10 or so minutes ... at which point the Cool Air LED turns red. How I would have done it? Well if you want an On/Off button (probably a good idea) then it should result in device on or off mode. If the device can't be turned off straight away then have an On and Cool Down mode, and indicate that Cool Down will result after a delay in device power-off. The other three things should be separate from the on/off control and would be labelled "Mode" or similar. In fact I'd probably have four switches: On/Cool Down, Power, Swing and Timer .. where "Power" would be "half" and "full" instead of 1000W and 2000W. Timer would have a perpetual state of "manual" unless otherwise selected. But I'm not an industrial designer ... there are people who do this for a living; though whoever designed this one should probably have put a bit more thought into it ... a bit more consideration for the end user.

There was a day when a vehicle heater was an optional add-on item. The heater unit usually hung under the dashboard on the passenger side (as shown here). This is a perfect example of vehicle history PA Farm Show (2009). Harrisburg, PA.