Seat Belt Reminder Lamp: Description and Operation

SEATBELT INDICATOR

DESCRIPTION
A seatbelt indicator is standard equipment on all instrument clusters. The seatbelt indicator is located near the lower edge of the instrument cluster, to the right of the multi-function indicator display. The seatbelt indicator consists of the International Control and Display Symbol icon for "Seat Belt" imprinted within a rectangular cutout in the opaque layer of the instrument cluster overlay. The dark outer layer of the overlay prevents the indicator from being clearly visible when it is not illuminated. A red Light Emitting Diode (LED) behind the cutout in the opaque layer of the overlay causes the icon to appear silhouetted against a red field through the translucent outer layer of the overlay when the indicator is illuminated from behind by the LED, which is soldered onto the instrument cluster electronic circuit board. The seatbelt indicator is serviced as a unit with the instrument cluster.

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 a hard wired input received from the seat belt switch on the driver side front seat belt. 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 input received by the cluster from the driver side front seat belt switch.
- Driver Side Front Seat Belt Switch Input - Following the seatbelt reminder function, each time the cluster detects ground on the seatbelt indicator driver circuit (seat belt switch closed = seatbelt unbuckled) with the ignition switch in the On position, the seatbelt indicator will be illuminated. The seatbelt indicator remains illuminated until the seat belt switch input to the cluster is an open circuit (seat belt switch open = seatbelt buckled), or until the ignition switch is turned to the Off position, whichever occurs first.
- Airbag Indicator Malfunction - Following the seatbelt reminder function, each time the cluster detects a malfunction in the airbag (SRS) indicator or the airbag indicator circuit, the cluster will flash the seatbelt indicator on and off. The cluster will continue to flash the seatbelt indicator until the airbag indicator circuit fault is resolved, or until the ignition switch is turned to the Off position, whichever occurs first.

The instrument cluster continually monitors the status of the driver side front seat belt switch and the airbag indicator circuit to determine the proper seatbelt indicator response. The seat belt switch is connected in series between the instrument cluster and ground. The seat belt switch and the seatbelt indicator driver circuit to the instrument cluster can be diagnosed using conventional diagnostic tools and methods. For proper diagnosis of the ACM, the air-bag (SRS) indicator, or the instrument cluster circuitry that controls the seatbelt indicator, a diagnostic scan tool is required. Refer to the appropriate diagnostic information.