Crash Sensors
Crash Sensors are the devices that work with the control module to discriminate between crash and non-crash events. These sensors measure the severity of the impact. They are set up so that sudden "negative acceleration" will cause the contacts to close, sending a signal to the control module which checks for a signal from the rear sensor which must arrive first to activate the Airbag(s). *It is important to note that at least 2 of these sensors must signal a crash before airbag deployment.
Sensor Types
By function, there are 2 types. Impact sensors and Safing sensors. The forward sensors are located in various locations forward of the passenger compartment. Some are located inside the fenders, some are on the cowl, some are attached to the core support in front of the radiator.
Rear SENSORS are also known as safing sensors as their function is to determine that a crash has occurred. Rear safing sensors are located in various locations in the passenger compartment depending on the manufacturer. Some are intergrated with the Control/Diagnostic Module.
The rear safing sensor must close before the forward sensors to avoid airbag deployment in cases where the impact is not severe enough to cause deployment. When the vehicle is parked with the ignition off deployment is very unlikely because there is no power to the circuits for deployment.
This means that someone can hit your car and sound the alarm but not deploy the airbags.
