Indicator, Seat Belt Reminder (SBR): Operation

WARNING: This page is about a different car, the 2017 Jeep Cherokee. However, it is still accessible from the selected car via links, so may be relevant.

The Seat Belt Reminder (SBR) indicator gives an indication to the vehicle operator and occupants of the status of the seat belt for each seating position of the vehicle. When a seat belt is buckled, the icon for that seating position is illuminated in green and when a seat belt is unbuckled, the icon for that seating position is illuminated in red. In the case of the larger icons representing the front seating positions, the indicator is illuminated in red only if the seat is occupied (the driver seat is assumed to be occupied while the status of the ignition is ON) and the seat belt is unbuckled, while the smaller icons representing the rear seating positions are illuminated in red with the seat belt unbuckled regardless of whether that seating position is occupied.

The Occupant Restraint Controller (ORC) monitors the status of each of the seat belt switches and the Occupant Detection Sensor (ODS) for the passenger side front seat. The ORC then sends the appropriate seat belt switch status messages over the Controller Area Network (CAN) data bus to the Instrument Panel Cluster (IPC). The IPC uses internal hardware and programming to interpret the messages from the ORC and manage both the audible and visual features of the seat belt reminder function. The IPC controls audible outputs related to the seat belt reminder through an on board transducer soldered to its Printed Circuit Board (PCB). The IPC is also a Local Interface Network (LIN) master node and uses a number of electronic command messages to control the visual output of the SBR indicator, which is a LIN slave node.

Besides the seat belt switch messages from the ORC, the IPC also monitors vehicle speed and the Reverse (R ) gear status in order to implement the various visual and audible outputs it controls. Besides the solid red or green indications, the SBR red indication may be flashed on and off, as dictated by the LIN bus message from the IPC. All seat belt reminder audible and visual indications have several pre-programmed counters that will cause the indications to change or cease upon expiration of certain timed intervals or due to a change of an input status. Some of the feature programming is mandated by state, provincial, local and federal regulations.

The SBR indicator is completely controlled by the IPC. The indicator receives a battery current input on a fused ignition (RUN) circuit and is connected to a path to ground at all times. Therefore, the SBR indicator will always be OFF when the status of the ignition switch (Keyless Ignition Node/KIN or IGnition Node Module/IGNM) is anything except ON.

The IPC and the ORC will store Diagnostic Trouble Codes (DTC) for any malfunctions they detect. The hard wired circuits between the SBR indicator and the IPC may be diagnosed using conventional diagnostic tools and procedures. Refer to the appropriate wiring information. However, conventional diagnostic methods will not prove conclusive in the diagnosis of the SBR indicator or the electronic controls and communication between other modules and devices that provide some features of the SBR. The most reliable, efficient and accurate means to diagnose the SBR indicator or the electronic controls and communication related to SBR indicator operation requires the use of a diagnostic scan tool. Refer to the appropriate diagnostic information.