WARNING: This page is about a different car, the 2004 Volvo S40, 2003 Volvo S40, 2002 Volvo S40, 2001 Volvo S40, and 2000 Volvo S40. However, it is still accessible from the selected car via links, so may be relevant.
Fig 1: Identifying Siren, Bolts and Connector
Courtesy of VOLVO CARS OF NORTH AMERICA.
Position the siren in the body (B) and (C).
Fit new bolt (A) and bolt (D). Tighten torque 10 Nm.