The front seat belts are equipped with pre‑tensioners that work in conjunction with the airbags in a severe frontal collision. The pre‑tensioners automatically retract both the seat belt anchor and the seat belt webbing, reducing slack in both the lap and diagonal portions of the belts, resulting in reduced forward movement of the occupant.
The rear outboard seats are equipped with shoulder pre- tensioners to retract the seat belt webbing to reduce forward movement of the occupant.
If the pre-tensioners and airbags did not activate in an impact, this does not mean they malfunctioned. It usually means that the strength or type of force needed to activate them was not present.
WARNING: Once the seat belt pre-tensioners have been activated, they must be replaced. After any collision, have the airbags, seat belt pre-tensioners and any associated components checked and, if necessary, replaced.
Testing Seat Belts
To confirm that seat belts are operating correctly, perform these three simple checks on each seat belt.
1. With the seat belt fastened, give the webbing nearest the buckle a quick pull. The buckle should remain securely locked.
2. With the belt unfastened, unreel the webbing to its limit. Check that unreeling is free from snags, and visually check the webbing for wear. Allow the webbing to retract, checking that retraction is smooth and complete.
3. With the webbing half unreeled, hold the tongue plate and pull forward quickly. The mechanism should lock automatically and prevent further unreeling.
If a seat belt fails any of these tests, contact Tesla immediately.