What is a seatbelt igniter and what does it do?

A seatbelt igniter is a critical component of a vehicle's seatbelt system that works in conjunction with the airbag system to enhance passenger safety during a collision. It is typically part of a seatbelt pre-tensioner mechanism.
 
Here’s what it does:
  1. Activation During a Crash: When a collision is detected, the vehicle's crash sensors send a signal to the seatbelt igniter.
  2. Ignition: The igniter uses a small pyrotechnic charge to rapidly activate the pre-tensioner.
  3. Pretensioning: This action pulls the seatbelt tight against the occupant's body, reducing slack and securing them firmly in their seat.
  4. Increased Safety: By tightening the seatbelt, the igniter helps position the occupant for optimal protection from the airbag and reduces the risk of injury caused by excessive movement during the crash.
 
In summary, a seatbelt igniter works to improve the overall effectiveness of the seatbelt and airbag systems during an accident, minimizing the likelihood of severe injuries.