Module - Occupant Restraint Controller: Description
The Airbag Control Module (ACM) (1) is also sometimes referred to as the Occupant Restraint Controller (ORC). The ACM is located below the instrument panel center stack in the passenger compartment of the vehicle, where it is secured by three screws to a stamped steel mounting bracket welded onto the top of the floor panel transmission tunnel just forward of the instrument panel center support bracket. Concealed within a hollow in the center of the die cast aluminum ACM housing is the electronic circuitry of the ACM which includes a microprocessor, an electronic impact sensor, an electronic safing sensor, and an energy storage capacitor. A stamped metal cover plate is secured to the bottom of the ACM housing with four screws to enclose and protect the internal electronic circuitry and components.
An arrow (2) printed on the label (3) on the top of the ACM housing provides a visual verification of the proper orientation of the unit, and should always be pointed toward the front of the vehicle. The ACM housing has integral mounting flanges on three corners. The mounting flange to the left of the connector receptacle has an integral locating pin on its lower surface. Both left side flanges have round mounting holes, while the flange on the right side has a slotted mounting hole. A molded plastic electrical connector (4) with two receptacles, one containing twenty-four terminal pins and the other containing thirty-two terminal pins, exits the rearward facing side of the ACM housing. These terminal pins connect the ACM to the vehicle electrical system through two dedicated take outs and connectors of the instrument panel wire harness.
The impact sensor and safing sensor internal to the ACM are calibrated for the specific vehicle, and are only serviced as a unit with the ACM. In addition, there are unique versions of the ACM for light and heavy-duty models, and for vehicles with or without the optional side curtain airbags. The ACM cannot be repaired or adjusted and, if damaged or faulty, it must be replaced.