Overheating Sensor
WARNING: This page is about a different car, the 2010 Volvo V70, 2009 Volvo V70, and 2008 Volvo V70. However, it is still accessible from the selected car via links, so may be relevant.
The overheating sensor helps the control module determine coolant temperature and thereby determine heater temperature and protect the heater from overheating.
The overheating sensor is integrated in the heater, located next to the coolant temperature sensor under a cover on one side of the heater.
There are diagnostics for the electronics of the overheating sensor.