Blower fan motor power unit, diagnostic signal, value
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2006 Volvo S80, 2005 Volvo S80, 2004 Volvo S80, 2003 Volvo S80, and 2002 Volvo S80. However, it is still accessible from the selected car via links, so may be relevant.
The climate control module (CCM) generates an analogue signal. This is converted to a current which the power unit converts back to an analogue signal. The diagnostic signal is an extremely intense signal that cannot be used when checking the blower fan.