Operation

Lights On Alarm Operation
When the lighting switch is moved to the side lamp or the headlamp position the feed from fusible link 12 passes through the lighting switch contacts and is connected to the passenger compartment fusebox on an R wire.

The feed passes to the Intelligent Driver's Module (IDM), which is integral with the passenger compartment fusebox. This feed is used as a side lights on signal by the logic circuits in the IDM and BCU.

The IDM is connected on the serial data bus link to pin C0661-1 on the BCU and to the instrument pack via header C0293 LHD/C0292 RHD by an SK wire. When the driver's door is opened the door switch contacts close, current flows from fuse 13 on a PN wire to pin C0660-13 on the BCU From pin C0660-17 on the BCU the current flows on a PW wire via header C0287 LHD/C0285 RHD to the closed contacts of the drivers door switch. From the closed contacts of the drivers door switch the current flows on a B wire through splice joint A34 to earth header C0017 LHD/C0018 RHD (also via header C0288 on LH drive vehicles).

The current flow from fuse 13 is used by the logic signals of the BCU to generate a door open output. The BCU communicates along the serial data bus with the IDM and the Instrument pack.

The two door open and lights on signals generate the appropriate lights on alarm output to the instrument pack.The sounder in the instrument pack emits the lights on signal and is earthed via the instrument pack.

For the system logic to generate a lights on alarm signal both the door open and lights on inputs must be present. If the light switch is turned off, the 'sidelights on' signal is removed With the loss of the input to the system the lights on alarm signal is cancelled by the logic circuits. If the door is closed when the side lights are on, the logic circuits will also cancel the lights on alarm signal.