Seat Belt Systems: Description and Operation
CIRCUIT OPERATIONWhen the Ignition is in RUN or START, voltage is applied to the passive restraint module's ignition Input (terminal 17). This signals the module to monitor the position of the shoulder belts. If the A-PILLAR Switch is open, indicating that the shoulder belt is at the A-PILLAR the passive restraint control module will apply power and ground to the appropriate shoulder belt motor until the shoulder belt reaches the B-PILLAR position.
When the shoulder belt reaches the B-PILLAR, the B-PILLAR switch opens which signals the module to cut-off power and ground to the SHOULDER BELT MOTOR. While the belt is moving, the module also turns on the shoulder belt indicator and the seat belt warning alarm for several seconds. The shoulder belt indicator will remain on after reaching the B-PILLAR if the LH Shoulder Belt Switch is closed indicating that the belt has not been buckled.
When the ignition switch is turned off and the key is removed, the passive restraint control module moves the shoulder belt to the A-PILLAR position. The module does this by applying voltage and ground to the Shoulder Belt Motors. The module cuts off power and ground to the motors when the A-PILLAR Switch opens, indicating the shoulder belt has reached the A-PILLAR.
The seat belt switch and the lap belts indicator operate independently of the automatic shoulder belts. The seat belt switch opens when the driver's lap belt is unbuckled. With the ignition switch in RUN or START and the driver's lap belt unbuckled, the lap belts indicator flashes and the seat belt warning alarm sounds for 5 seconds or until the belt is buckled.