SEAT WEIGHT SENSOR

Vehicles equipped with the Occupant Classification System (OCS) have a seat weight bladder (2) and pressure sensor (5) unit that is integral to the passenger side front seat cushion. The bladder is sandwiched between the seat cushion springs and seat cushion foam. A heavy jute-like insulator pad (3) is installed between the lower surface of the bladder and the seat cushion springs. The pad is secured to the underside of the bladder by diagonal straps that form pockets at each of the two rear corners of the bladder, while two plastic push-in fasteners (1) locate and secure the forward edge of the bladder and the pad to the front edge of the seat cushion frame. The seat cushion foam is installed loosely over the top of the bladder, then secured by the installation of the trim cover to the seat cushion.

The bladder consists of two rectangular sheets of an elastomeric material and a molded plastic elbow fitting. The two sheets of material are sealed together around their perimeter and heat staked to each other at numerous regular points within their field. The elbow fitting is sealed to a small round hole in the lower surface of the bladder and is pointed downward where it passes through a clearance hole in the insulator pad and extends to just below the seat cushion springs. Then the bladder is filled with a silicone fluid to become a pliable, quilted membrane.

Under the seat cushion a short tube (4) is securely clamped at one end to the bladder nipple, and at the other end to a nipple on the electronic pressure sensor. The pressure sensor is contained within a molded plastic housing with an integral nipple formation near one end and an integral electrical connector receptacle at the opposite end. The sensor housing also features an integral mount that snaps over a tab integral to the stamped steel Occupant Classification Module (OCM) mounting bracket welded to the underside of the passenger side front seat cushion frame. The pressure sensor connector receptacle contains terminal pins that connect the sensor to the vehicle electrical system and the OCM through a dedicated take out and connector of the passenger side front seat wire harness.

The seat weight bladder and pressure sensor cannot be adjusted or repaired. The components of the passenger side front seat cushion of a vehicle equipped with the OCS including the cushion frame, springs, insulator pad, seat weight bladder and pressure sensor, seat cushion foam, wire harness and the OCM are serviced only as a factory-calibrated, assembled and tamper-evident unit. Only the OCM and the seat cushion trim are available for separate service replacement. Once a service replacement package has been installed in a vehicle, the OCM can thereafter be serviced only by replacing the entire passenger side front seat cushion unit with another complete service replacement package.

REMOVAL

If any of the Occupant Classification System (OCS) components of the passenger side front seat cushion require replacement, they are serviced only as a factory-calibrated, assembled, and tamper-evident service replacement package. This package includes the assembled frame, springs, pad, seat weight bladder and pressure sensor, foam, wiring and a calibrated Occupant Classification Module (OCM). When installing this package, always replace all of the existing components with the new components as a unit. Do not attempt to separate or disconnect any of the new OCS components contained in the service replacement package from each other, and do not attempt to reuse any of the replaced components in this or any other vehicle.

Once any of the original factory-installed components except the OCM have been replaced with the service replacement package components, the OCM can only be serviced by replacing the entire passenger side front seat cushion unit with another complete service replacement package. Any time any one of these components is removed or replaced for any reason, the OCM must be re-calibrated using a diagnostic scan tool, the Occupant Classification Seat Weight special tool, and the Occupant Classification System Verification Test. Refer to the appropriate diagnostic procedures.

WARNING: To avoid personal injury or death, on vehicles equipped with airbags, disable the supplemental restraint system before attempting any steering wheel, steering column, airbag, occupant classification system, seat belt tensioner, impact sensor, or instrument panel component diagnosis or service. Disconnect and isolate the battery negative (ground) cable, then wait two minutes for the system capacitor to discharge before performing further diagnosis or service. This is the only sure way to disable the supplemental restraint system. Failure to take the proper precautions could result in accidental airbag deployment.

WARNING: To avoid personal injury or death on vehicles equipped with the Occupant Classification System (OCS), only the Occupant Classification Module (OCM) and the seat cushion trim may be serviced separately. All other components of the passenger side front seat cushion assembly must be serviced only as a complete factory-calibrated, assembled and tamper-evident service replacement package. This package includes the frame, springs, pad, bladder and pressure sensor, foam, wiring and a calibrated OCM. When installing this package always replace all of the existing components with the new components as a unit. Do not attempt to separate or disconnect any of the new OCS components in the service replacement package from each other, and do not attempt to reuse any of the replaced components in this or any other vehicle. Failure to take the proper precautions could result in failure of the passenger airbag to deploy when required, or in passenger airbag deployment when not required.

WARNING: To avoid personal injury or death on vehicles equipped with the Occupant Classification System (OCS), do not modify the front passenger seat assembly or center floor console in any way. Do not use any prior year, subsequent year, secondary or aftermarket seat trim covers. At no time should any Supplemental Restraint System (SRS) or OCS component be modified or replaced with any part except those which are specified for the particular vehicle application in the DaimlerChrysler Mopar® Parts Catalog. Failure to observe these precautions could cause an OCS miscalibration condition, which may result in the passenger airbag failing to deploy when required or deploying when not required.

CAUTION: On vehicles equipped with the Occupant Classification System (OCS), never replace both the Airbag Control Module (ACM) (also known as the Occupant Restraint Controller/ORC) and the Occupant Classification Module (OCM) at the same time. If both require replacement, replace one. Then perform the supplemental restraint verification test before replacing the other. Both the ACM and the OCM store OCS calibration data, which they transfer to one another when one of them is replaced. If both are replaced at the same time, an irreversible fault will be set in both modules.