Volvo VNL 780 Operator's Manual page 290

280 OPERATION
The retractor web storage device is mounted on the B-pillar, just behind the door in the cab.
The retractor is the heart of the safety belt system and can be damaged if abused, even
unintentionally. Check the retractor web storage device operation to ensure that it is not
locked and that it spools out and retracts the webbing properly.
W8002481
If tethers are being used to anchor the safety belts to the floor, make sure that they are
properly attached to the seat. Tethers must also be inspected for web wear and proper
tightness of mounting hardware.