Aux Cabin Heater Normal Operating Range Please?

[Johnnydrhodes]

Can anyone explain how/when the Auxiliary Cabin should work. My understanding is it is designed to operate until the engine reaches a temperature that allows the heat to be drawn from the engine instead. On mine it doesn't seem to go off unless it's naturally hot in the cabin ( e.g. Sunlight) or if I turn the settings down below say 20. My engine gauge reads anywhere between 1/4 and 1/3, sometimes just below 1/2 but that squigely or orange light doesn't go out? My car is under warranty and taken it in twice now with no joy.

[crispinchurch]

When the temperature rises to reach 72 °C the heater switches to the energy saving part load operation. A rise in temperature up to 76.5 °C causes the heater to enter a control idle period. This also happens when exceeding a total heating operating time of 76 minutes. The circulation pump, the vehicle's own heating air fan, and the operation indicator light remain on during control idle. After cool-down of the coolant to 71 °C the heater resumes part load operation. Another rise in temperature to 76.5 °C causes the heater to enter again the control idle period. A drop in the coolant temperature during part load operation due to an increased demand in heat will cause the heater to switch to full load operation at 56 °C.