Commander 4WD V8-4.7L VIN N (2006)
Seat Sensor/Switch: Description and Operation
Seat Weight Sensor
SENSOR-SEAT WEIGHT
DESCRIPTION
The seat weight sensors are strain gauge-type units. The electronic elements of the sensor are encased in a potting material within the molded plastic
sensor housing (1). Four sensors are used in the Occupant Classification System (OCS). A sensor is located at each corner of the passenger side front
seat.
The strain gauge for each sensor is secured through three mounting bosses (2) by three screws and nuts between the seat riser frame and the seat adjuster
tracks. A molded connector receptacle (3) integral to each sensor housing is connected to the vehicle electrical system through a dedicated connector and
take out of the passenger seat wire harness beneath the seat cushion.
The seat weight sensors cannot be adjusted or repaired and, if faulty or damaged, the entire sensor must be replaced.
OPERATION
The seat weight sensor units are designed to sense the relative weight of a load applied to the passenger side front seat, which provides a logic input to
the microprocessor of the Occupant Classification Module (OCM). When a load is applied to the seat, the strain gauge of each sensor is flexed causing a
change of electrical resistance through the strain gauge. These changes in resistance are measured by the sensor and the internal sensor circuitry changes
the sensor output voltage.
Each weight sensor receives a nominal five volts and a ground through parallel hard wired circuits from the OCM. The OCM then monitors the output
voltage of each sensor on dedicated hard wired data communication circuits. The hard wired circuits between the sensors and the OCM may be
diagnosed and tested using conventional diagnostic tools and procedures. However, the most reliable, efficient, and accurate means to diagnose the seat
weight sensor inputs to the OCM, and the electronic message communication between the OCM and the Occupant Restraint Controller (ORC) requires
the use of a diagnostic scan tool.
