Seat Belt Reminder Lamp: Description and Operation
The seatbelt indicator gives an indication to the vehicle operator of the status of the driver side front seat belt. This indicator is controlled by a transistor
on the instrument cluster circuit board based upon cluster programming and electronic messages received by the cluster over the Controller Area
Network (CAN) data bus from the Occupant Restraint Controller (ORC) (also known as the lowline or highline airbag control unit/ARCADE).
The seatbelt indicator Light Emitting Diode (LED) is completely controlled by the instrument cluster logic circuit, and that logic will only allow this
indicator to operate when the instrument cluster detects that the ignition switch is in the ON position. Therefore, the LED will always be OFF when the
ignition switch is in any position except ON. The LED only illuminates when it is provided a path to ground by the instrument cluster transistor. The
instrument cluster will turn ON the seatbelt indicator for the following reasons:
Seatbelt Reminder Function - Each time the cluster detects that the ignition switch has been turned to the ON position the seatbelt indicator will
be illuminated as a reminder for about six seconds, or until the ignition switch is turned to the OFF position, whichever occurs first. This reminder
function will occur regardless of the status of the driver side front seat belt switch.
Seatbelt Indicator Lamp-On Message - Following the seatbelt reminder function, each time the cluster receives an electronic seatbelt indicator
lamp-ON message from the ORC, the seatbelt indicator will be illuminated. The indicator remains illuminated until the cluster receives a
lamp-OFF message from the ORC, or until the ignition switch is turned to the OFF position, whichever occurs first. On vehicles equipped with the
optional steering wheel buttons, each time the cluster receives an electronic seatbelt indicator lamp-ON message from the ORC, a Seatbelt sys.
- Visit workshop textual message will appear within the cluster multi-function display. The textual message remains displayed until the cluster
receives a lamp-OFF message from the ORC, or until the ignition switch is turned to the OFF position, whichever occurs first.
The ORC continually monitors the status of the driver side front seat belt switch and circuits to determine whether the seatbelt is buckled. The ORC then
sends the proper lamp-ON or lamp-OFF message to the ElectroMechanical Instrument Cluster (EMIC) (also known as the Cab Compartment Node/CCN
or KOMBI). If the ORC sends a lamp-ON message after the seatbelt reminder function, it indicates that the ORC has detected that the seatbelt is not
buckled or that the seatbelt switch and circuits are ineffective. The ORC will store a Diagnostic Trouble Code (DTC) for any malfunction it detects.
For proper diagnosis of the seatbelt switch, the ORC, the EMIC, the CAN data bus or the electronic communication related to seatbelt indicator
operation, a diagnostic scan tool is required. Refer to the appropriate diagnostic information.