Chrysler 300/300 Touring/300C, Dodge Magnum. Manual - part 756
SEAT WEIGHT SENSOR
DESCRIPTION
The seat weight sensors (4) are strain gauge-type
units. The electronic elements of the sensor are
encased in a potting material within the molded plastic
sensor housing. Four sensors (4) 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 by three
screws and nuts (2) between the seat cushion frame
and the seat adjusters (3). A molded connector recep-
tacle (1) 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 frame.
The seat weight sensors cannot be adjusted or
repaired and, if faulty or damaged, the entire sensor
must be replaced.
WARNING: The Seat Weight Sensor is a sensitive, calibrated unit and must be handled carefully. Do not
drop or handle roughly. If dropped or damaged, replace with another sensor. Failure to do so may result in
occupant injury or death.
WARNING: The front passenger seat must be handled carefully as well. When removing the seat, be careful
when setting on floor not to drop. If dropped, the sensor may be inoperative, could result in occupant
injury, or possibly death.
WARNING: When the seat is on the floor, no one should sit in the front passenger seat. This uneven force
may damage the sensing ability of the seat weight sensors. If sat on and damaged, the sensor may be
inoperative, could result in occupant injury, or possibly death.
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 diag-
nostic 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. Refer to the appropriate diagnostic informa-
tion.
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RESTRAINTS - SERVICE INFORMATION
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