Check the cable terminal locking tabs
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.
If the cable terminal has locking tab/locking tabs, check that they are not damaged or pressed inward so they will not engage when the terminal is inserted in a housing.