Keep in mind the following
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.
The secondary locking must always be adjusted to the initial position.
The secondary locking must be closed in reverse order to the way it was opened.
When the secondary locking is closed a "click" is often heard.
If it cannot be closed it might be because the cable terminal is not completely inserted in the cavity.
If the connector has a sheath, cover or rubber gasket for the housings, do not forget to reinstall it.