A: The only way the seat belt can know if it’s buckled is with a switch that is built into the latching part of the buckle. The switch on older vehicles (pre-airbag) triggered the seat belt warning light directly. On newer vehicles, the switch signal is read by the SRS, GEM, or a “smart junction box,” which is a fuse panel that has a computer built in.
The switch on older vehicles (pre-airbag) triggered the seat belt warning light directly.
– Richard McCuistian, ASE Certified Master Automobile Technician
The seat belt sensor is part of a vehicle’s passenger safety system. It detects when the seat belts in the vehicle are fastened while a passenger is sitting on a seat. If the seat belt isn’t fastened over a rider, then the seat belt sensor will trigger the seat belt warning light while playing a pinging sound.
If the occupant restraint sensor in the seat indicates there’s weight in the seat but the seat belt isn’t buckled, the passenger airbag may be disabled along with a warning light that the passenger side airbag is turned OFF.
The following steps usually allow access to the seat belt sensor:
Refer to your vehicle’s manual or talk to a mechanic if you can’t locate the sensor yourself.
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