Volvo V40 Owner's Manual page 306

08 Starting and driving
||
The indicator window must show red.
Insert the towball section until you hear a
click.
08
304
The indicator window must show green.
Turn the key anticlockwise to locked
position. Remove the key from the lock.
Check that the towball section is secure
by pulling it up, down and back.
WARNING
If the towball is not fitted correctly then it
must be detached and reattached in
accordance with the previous instructions.
IMPORTANT
Only grease in the ball for the towball
hitch, the remainder of the towbar must be
clean and dry.