Rear Fog Guard Lamp Switch Operation (Description and operation)

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.

Rear Fog Guard Lamp Switch Operation

When the rear fog guard lamp switch is operated, an earth path is completed from the BCU pin 662-8 to the switch on a UP 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 rear fog guard lamp relay, through the two IDM electronic switches to the BCU on the SK wire.

The energised coil closes the contacts of the rear fog guard lamp relay. This allows the feed from fuse 4 in the passenger compartment fusebox to flow through the relay contacts.

From the fusebox the feed is connected on a RY wire, to connector interface C0020-1/C0905-1. From this interface the feed continues on a R wire to connector interface C0905-2/C0020-2. From this interface the feed continues on a RY wire to the trailer pick-up socket.

From the connector interface C0905-2/C0020-2, the feed is connected on a Y wire to connector interface C0905-3/C0020-3. From this interface the feed is connected on an RY wire to header C0295.

A feed from header C0295 is connected on an RY wire to the RH rear fog guard lamp which in turn is connected to earth header C0706 on a B wire.

A second feed from header C0295 is connected on a RY wire to the LH rear fog guard lamp which in turn is connected to earth header C0707 on a B wire.