Front Fog Lamps Operation

Lighting Switch Operation
When the lighting switch is moved to the side lamp or headlamp position, the feed from fusible link 13 passes through the switch contacts, and is connected from the lighting switch to the passenger compartment fusebox on an R wire. The feed is connected to the IDM causing the second of the two electronic switches to close.

Body Control Unit Operation
The feed from fuse 13 passes through the two closed IDM switches and is connected by an SK wire to BCU pin C0661-1, via header C0293 LHD/ C0292 RHD. This connection is the serial data bus between the BCU and the IDM.

The BCU is connected to earth header C0551 from pin C0660-11 on a B wire and from pin C0664-5 on a B wire to earth header C0018 LHD/C0017 RHD.

Front Fog Lamps Operation
When the front fog lamp switch is operated, an earth path is completed from the BCU pin C0660-7 to the switch on a KB wire. The earth path continues through the switch contacts and is connected to earth header C0017 LHD/C0018 RHD on a B wire via header C0760.

The completion of the earth path signals the BCU to provide an earth path from the coil of the front fog lamp relay in the engine compartment fuse box to the BCU pin C0663-4 on a UY wire.

The energised coil closes the contacts in the front fog lamp relay. This allows the feed from fuse 3 to pass through the relay contacts and from the engine compartment fusebox to header C0293 on a UP wire.

From the header C0293, the feed is connected on a UP wire to the RH front fog lamp, which connected to earth header C0018 by a B wire.

A second teed from the header C0293 is connected on a UP wire to the LH front fog lamp, which is connected to earth point C0564 by a B wire.

Switch indicator lamp operation
A third feed from header C0293 is connected to the front fog lamp switch on a UP wire. The feed passes through the front fog lamp switch indicator lamp which illuminates. The indicator lamp is earthed from the front fog lamp switch to earth header C0017 LHD/C0018 RHD, via header C0760 on a B wire.