Discovery II
INSTRUMENTS
DESCRIPTION AND OPERATION
88-31
Seat belt warning lamp
The seat belt warning lamp within the instrument pack utilises a red LED and a clear legend. The BCU utilises a switch
in each of the front seat belt buckles to determine if a seat belt is not fastened.
When the ignition is switched on, the BCU illuminates the LED for 6 seconds or until the BCU determines that a seat
belt is fastened which extinguished the warning lamp. This provides the driver with a visible reminder that the seat
belts are not fastened.
The instrument pack provides the self-check if the diagnostic connector fails.
The power input for the LED is supplied by the instrument pack via fuse 13. The BCU provides the earth path to
illuminate the seat belt warning lamp.
The seat belt buckle switches complete the earth path in the BCU sensing circuit, the BCU commands the instrument
pack to switch on the seat belt warning lamp.
The BCU earth path to the seat belt buckle is as follows:
l
< 1.8 volts = warning lamp off.
l
> 7.7 volts = warning lamp off.
