Combustion Air Fan
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 combustion air fan sucks in air from the air intake and forces the air into the combustion chamber during combustion.
The combustion air fan is integrated in the heater, located below the control module.
There are diagnostics for the electronics of the combustion air fan.