Description And Operation: Description
The buckles of driver and front and rear passenger seats are equipped with a sensor that checks the fastening and differ depending on the market:
Europe-Middle East-Africa (EMEA) version
- Driver side Hall-effect sensor
- Resistive sensors on anchorage of front and rear passenger buckles
North America Free Trade Agreement (NAFTA) version
- Driver and front passenger side Hall-effect sensor
The resistive and Hall-effect sensors are hardwired to, and monitored by the Occupant Restraint Controller (ORC). When the latch plate is inserted into the buckle it pushes on the spring device and the window of the slide aligns between the Hall-effect sensor and the permanent magnet. When the sensor and the magnet align, the Hall-effect sensor changes state indicating that the seat belt is fastened.
A 1 kilohm diagnostic resistor is connected in parallel with the Hall-effect sensor where the two pigtail wire leads connect to the Hall-effect sensor pins. The resistor allows a small amount of current to flow through the circuit continuously. The ORC monitors the current in the circuit. When 5-8 mA are present, the seat belt is unbuckled. When 12-17 mA are present, the seat belt is buckled. If the harness is disconnected, the current flow is interrupted and a seat belt switch DTC is set.
The resistive sensor is based on the current flowing through a normally closed contact.
The rated current is about 10 mA while the operating current will be approximately between 10 mA and 400 mA.
The seat belt switches cannot be adjusted or repaired and, if ineffective or damaged, the entire front or rear seat belt buckle-half unit must be replaced.