Defender Electric Diagrams. Manual - part 17

CIRCUIT OPERATION

DEFENDER 90 NAS

REV: 9/97

EXTERIOR LAMPS - Brake and Reverse Lamps

DESCRIPTION

The brake lights on the rear of the vehicle illuminate with the ignition switched on and the
brake pedal depressed.

The reverse lights on the rear of the vehicle illuminate with the ignition switched on and
the gear selector lever in reverse position.

OPERATION

Feed from the positive battery terminal is connected to the engine compartment fuse box
(C632-1) by the brown wire. Current passes through fusible link 1 and fusible link 5 of
the engine compartment fuse box which are connected in series. Fusible link 5 of the
engine compartment fuse box (C570-2) is connected to the ignition switch (C028-1) by
the brown wire.

When the ignition switch is in position 'II', power flows across the ignition switch (C94-1)
to fuses 17 and 18 of the passenger compartment fuse box (C581-13) on the white wire.
Fuse 17 of the passenger compartment fuse box feeds the brake light circuit. Fuse 18 of
the passenger compartment fuse box feeds the reverse light circuit.

Brake lights

Fuse 17 (C581-14) of the passenger compartment fuse box is connected to the brake
pedal switch (C75-1) by the green wire. When the brake pedal is depressed, the brake
pedal switch closes and power flows through the switch. The brake pedal switch (C029-
1) is connected to the LH tail light (C404-2), RH tail light (C401-2), trailer connector
(C029-1) and high mounted brake light harness (C406-1) by green/purple wires. The high
mounted brake light (C972-1) is supplied a feed via a separate harness on a red wire. All
brake lights are grounded on black wires.

Reverse light

Fuse 18 (C581-16) is connected to starter inhibitor/reverse light switch (C69-2) by the
green wire. When the gear selector is in the reverse position, the reverse light switch is
closed. Current from fuse 18 flows across the reverse light switch (C69-3) to the reverse
light (C167-1) and trailer connector (C699-1) by green/brown wires. Both reverse light
and trailer connector are grounded by black wires.

CIRCUIT OPERATION

DEFENDER 90 NAS

EXTERIOR LAMPS - Head, Side and Number Plate Lamps

DESCRIPTION

The lights are operated from the lighting switch located on the steering column. The
lighting switch has 2 positions. Position 1 switches on the tail lights and front sidelights,
position 2 additionally switches on the front headlights. When the headlights are on, the
column switch can be used to switch between main beam and dipped beam.

The headlights can be flashed with the lights on or off, by pulling the column switch
towards the driver.

OPERATION

Side lights

Feed from the positive battery terminal is connected to the engine compartment fuse box
(C632-1) by the brown wire. Current passes through fusible link 1 and fusible link 4 of
the engine compartment fuse box which are connected in series. Power from fusible link 4
of the engine compartment fuse box (C573-2) feeds the lighting switch (C41-1) on a
brown wire. With the lighting switch in the side lights position, power flows through the
light switch (C41-2) to passenger compartment fuse box (C581-1) fuses 11 and 12 on a
red wire. Fuse 11 feeds the trailer connector (C499-7), number plate illumination light
(C139-1), LH tail light (C404-3), LH rear side marker light (C405-1), LH front side
marker light (C13-1) and LH front side light (C538-1). All lights are grounded on black
wires. Fuse 12 feeds the trailer connector (C499-1), RH tail light (C401-3), RH rear side
marker light (C400-1), RH front side marker light (C12-1) and RH front side light (C537-
1). All lights are grounded on black wires.

Headlights

Fusible link 5 of the engine compartment fuse box (C570-2) is connected to the ignition
switch (C28-1) by the brown wire. With the ignition switch in position 'II', power flows
across the ignition switch (C94-1) to fuse 1 of the passenger compartment fuse box
(C580-1) on the white wire. Fuse 1 is connected to the headlight solenoid winding
(C282-85) by the white/green wire. The headlight solenoid winding is grounded (C282-
86) on a black wire. With the headlight solenoid energized, the relay switches to allows
power to flow across the relay.

When the lighting switch is in the headlight position, power from fusible link 4 of the
engine compartment fuse box flows through the lighting switch (C41-4) to the headlight
relay (C282-87) on a blue/yellow wire. Provided the solenoid is energized, by the
ignition being switched on, power flows through the headlight relay (C282-30) to the
column switch (C36-1) on a blue wire.

CIRCUIT OPERATION

DEFENDER 90 NAS

With the column switch in the dip position, power from the column switch (C36-6) is fed
to fuses 7 and 8 of the passenger compartment fuse box (C580-13) on a blue/red wire.
With the column switch in the main beam position, power from the column switch (C36-
5) is fed to fuses 9 and 10 of the passenger compartment fuse box (C580-17) on a
blue/white wire via a header joint (C289). A feed is also supplied through the header
joint (C289) to the instrument pack main beam warning light (C233-5) on a blue/white
wire and grounded on a black wire.

Fuse 7 supplies the RH front dipped headlight (C11-2) on a blue/black wire. Fuse 8
supplies the LH front dipped headlight (C9-2) on a blue/pink wire. Fuse 9 supplies the
RH front main beam headlight (C11-1) on a blue/orange wire. Fuse 10 supplies LH front
main beam headlight (C9-1) on a blue/slate wire. All lights are grounded on black
wires.

Headlight flash

A continuous feed from fusible link 1 through fuse 2 of the engine compartment fuse box
(C574-3) is supplied to the column switch (C36-7) on a purple wire. When the headlight
flash switch is operated, power flows through the switch (C36-5) to fuse 9 and 10 of the
passenger compartment fuse box (C580-17) on a blue/white wire. Power is also supplied
from the switch to the instrument pack main beam warning light (C233-5) on a blue/white
wire via a header joint (C289). All lights are grounded on black wires.

CIRCUIT OPERATION

DEFENDER 90 NAS

EXTERIOR LAMPS - Lights On Alarm

DESCRIPTION

If the side lights are switched on when the ignition is in the off position, opening either
the driver's door or passenger's door will cause the lights on alarm to sound.

OPERATION

Feed from the positive battery terminal is connected to the engine compartment fuse box
(C632-1) by a brown wire. Current passes through fusible link 1 and fusible link 5 of the
engine compartment fuse box which are connected in series. Fusible link 5 (C570-2) is
connected to the ignition switch (C28-1) by a brown wire.

With the ignition switch in position 'II', power flows through the ignition switch (C94-1)
to fuse 1 of the passenger compartment fuse box (C580-1) on the white wire. Fuse 1
(C580-2) supplies the multi-function ECU (C16-2) on the white/green wire. If the ECU
receives a signal from the ignition switch, the lights on alarm will not sound.

Fusible link 4 of the engine compartment fuse box (C573-2) is connected to the lighting
switch (C41-1) by the brown wire. With the lighting switch on, power flows through the
switch (C41-2) to fuse 11 of the passenger compartment fuse box (C581-1) on the red
wire. Fuse 11 (C581-2) is connected to the dimmer circuit (C285-7) on the red/black
wire and from the dimmer circuit (C285-15) to the lights on sounder, located in the ECU
(C16-4), on the red/white wire.

Fuse 2 of the engine compartment fuse box (C574-3) supplies the ECU with a permanent
feed on the purple wire. The ECU is connected to the driver's door switch (C266-1) by
the purple/green wire. The ECU is connected to the passenger's door switch (C265-1) by
the purple/white wire. Opening either door closes a door switch, connecting the ECU to
ground. Provided the ECU is receiving a lights on signal (C16-4) but no ignition signal
(C16-2), the lights on alarm ground is switched to a black wire (C16-6) and the alarm
sounds.

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