RAM 2500 Truck 4WD L6-5.9L DSL Turbo VIN 6 (1999)
Impact Sensor: Description and Operation
Impact and Safing Sensors
One electronic impact sensor is used in this airbag system. The impact sensor is an accelerometer that senses the rate of vehicle deceleration, which
provides verification of the direction and severity of an impact. The impact sensor is calibrated for the specific vehicle, and is only serviced as a unit
with the ACM. A pre-programmed decision algorithm in the ACM microprocessor determines when the deceleration rate as signaled by the impact
sensor indicates an impact that is severe enough to require airbag system protection. When the programmed conditions are met, the ACM sends an
electrical signal to deploy the airbags.
In addition to the electronic impact sensor, there is an electromechanical sensor within the ACM called a safing sensor. The safing sensor is a normally
open series switch located in the airbag deployment circuit of the ACM. This sensor detects impact energy of a lesser magnitude than the electronic
impact sensor, and must be closed in order for the airbags to deploy.