Land Rover Discovery 99my To 03my Electrical Library 3rd Edition Rover Manual

							DESCRIPTION AND OPERATION
4.20DISCOVERY SERIES II
Front sunroof tilt detection
The front sunroof motor is connected to pin C0784-8 on the sunroof ECU by an OU wire. An 
input to the sunroof ECU via this connection forms a sunroof tilt input to the sunroof ECU.
Front sunroof - open function
When the front sunroof switch is set to the open position, an earth path from pin C0784-2 to 
the front sunroof switch on a GK wire is completed. From the front sunroof switch the earth 
continues to earth header C0018 via splice joints A14 and A15. The sunroof ECU logic 
circuit monitors a current flow from pin C0784-2. This current flow forms the open input to 
the sunroof ECU, and the ECU logic supplies a power feed to pin C0785-5.
The feed flows from pin C0785-5 on the sunroof ECU to the sunroof motor on a P wire. The 
front sunroof motor is earthed on a B wire via splice joints A14 and A15 to earth header 
C0018.
The sunroof motor drives the sunroof mechanism towards the open position. When the 
sunroof switch is released, the earth path via the sunroof switch is interrupted and the open 
input to the sunroof ECU is lost. The sunroof ECU logic circuits remove the power supply to 
pin C0785-5, this removes the power supply from the sunroof motor.
Front sunroof - close function
When the front sunroof switch is set to the close position, an earth path from pin C0785-7 of 
the sunroof ECU to the front sunroof switch is completed on a GR wire. The front sunroof 
switch is earthed via splice joints A14 and A15 to earth header C0018 on a B wire. The 
sunroof ECU logic circuit monitors a current flow from pin C0785-7. With this current flow 
forming a close input the sunroof ECU logic supplies a power feed to pin C0785-1.
The feed flows from pin C0785-1 of the sunroof ECU to the sunroof motor on a W wire. The 
front sunroof motor is earthed on a B wire via splice joints A14 and A15 to earth header 
C0018. The sunroof motor drives the sunroof mechanism towards the close position.
When the sunroof switch is released, the earth path via the sunroof switch is interrupted and 
the close input to the sunroof ECU will be lost. The sunroof ECU logic circuits remove the 
power supply to pin C0785-1, this removes the power supply from the sunroof motor.
Rear sunroof operation
Rear sunroof tilt detection
The rear sunroof motor is connected to pin C0784-1 on the sunroof ECU by a OG wire. An 
input to the sunroof ECU via this connection forms a sunroof tilt input to the sunroof ECU. 
						

							DESCRIPTION AND OPERATION
DISCOVERY SERIES II 4.21
Rear sunroof operation - via front switch 1
Rear sunroof - open function - via front switch 1
When the rear 1 sunroof switch is set to the open position, an earth path from pin C0784-7 
of the sunroof ECU to the to sunroof switch is completed on a GU wire. From sunroof switch 
1 the earth continues via splice joints A14 and A15 to earth header C0018 on a B wire. The 
sunroof ECU logic circuit monitors the current flow from pin C0784-7. With this current flow 
forming an open input the sunroof ECU logic supplies a power feed to pin C0785-4.
The feed flows from pin C0785-4 of the sunroof ECU to the rear sunroof motor on an U wire. 
The rear sunroof motor is earthed on two B wires via splice joints A14 and A15 to earth 
header C0018. The sunroof motor drives the sunroof mechanism towards the open position.
When the sunroof switch is released, the earth path via the sunroof switch is interrupted and 
the open input to the sunroof ECU will be lost. The sunroof ECU logic circuits remove the 
power supply to pin C0785-4, this removes the power supply from the sunroof motor.
Rear sunroof - close function - via front switch 1
When the rear sunroof switch 1 is set to the close position, an earth path from pin C0785-8 
on the sunroof ECU to the rear sunroof switch 1 is connected on a GO wire. The rear sunroof 
switch 1 is earthed via splice joints A14 and A15 to earth header C0018 on a B wire. The 
sunroof ECU logic circuit monitors a current flow from pin C0785-8. With a current flow 
forming an close input the sunroof ECU logic supplies a power feed to pin C0785-6.
The feed flows from pin C0785-6 on a O wire to the rear sunroof motor. The rear sunroof 
motors are earthed on a B wire via splice joints A14 and A15 to earth header C0018. The 
sunroof motor drives the sunroof mechanism towards the close position.
When the sunroof switch is released, the earth path via the sunroof switch is interrupted and 
the close input to the sunroof ECU will be lost. The sunroof ECU logic circuits remove the 
power supply to pin C0785-6, this removes the power supply from the sunroof motor.
Rear sunroof operation - via rear switch 2
Rear sunroof switch 2 - isolation
An isolation switch is connected by an BS wire to the rear sunroof switch 2. From the 
isolation switch a B wire is connected to earth via splice joints A14 and A15 to earth header 
C0018. When the isolation switch is pressed the earth line from the rear sunroof switch 2 is 
interrupted. This function allows the driver or front seat passenger to disable the rear sunroof 
switch 2. 
						

							DESCRIPTION AND OPERATION
4.22DISCOVERY SERIES II
Rear sunroof switch 2 - normal operation
Rear sunroof - open function - via switch 2
When the rear 2 sunroof switch is set to the open position, an earth path from pin C0784-6 
on a GW wire is completed via the closed contacts of the isolation switch, and on a B wire 
via splice joints A14 and A15 to earth header C0018. The sunroof ECU logic circuit monitors 
the current flow from pin C0784-6. With this current flow forming an open input the sunroof 
ECU logic supplies a power feed to pin C0785-4.
The feed flows from pin C0785-4 on an OU wire to the rear sunroof motor. The rear sunroof 
motor is earthed on a B wire via splice joints A14 and A15 to earth header C0018. The 
sunroof motor drives the sunroof mechanism towards the open position.
When the sunroof switch is released, the earth path via the sunroof and isolation switches 
is interrupted. The open input to the sunroof ECU will be lost and the sunroof ECU logic 
circuits remove the power feed to pin C0785-4, this removes the power supply from the 
sunroof motor.
Rear sunroof - close function - via switch 2
When the rear sunroof switch 2 is set to the close position, an earth path from pin C0785-9 
on a GB wire is completed via the closed contacts of the isolation switch, and on a B wire 
via splice joints A14 and A15 to earth header C0018. The sunroof ECU logic circuit monitors 
the current flow from pin C0785-9, this current flow forms a close input and the sunroof ECU 
logic supplies a power feed to pin C0785-6.
The feed flows from pin C0785-6 on a O wire to the rear sunroof motor. The sunroof motor 
drives the sunroof mechanism towards the close position. When the sunroof switch 2 is 
released, the earth path via the sunroof switch is interrupted. The close input to the sunroof 
ECU is lost and the sunroof ECU logic circuits remove the power supply to pin C0785-6. This 
removes the power supply from the rear sunroof motor.
Sunroof motor protection
Control functions of the sunroof ECU prevent damage to the sunroof motors at full travel 
positions when the operating switch is still pressed:
zCurrent (step) sensing
zA backup seven second time delay after movement has stopped.
NOTE: Either of these control functions will stop the operation of the sunroof motors at the 
end of travel positions. 
						

							DESCRIPTION AND OPERATION
DISCOVERY SERIES II 4.23
Ignition key modes
Depending on the vehicles specification:
The sunroof ECU controls operation of both sunroofs and will allow sunroof operation for a 
period of 44 seconds after the ignition switch is moved to the off position.
On some models if the time is less than 44 seconds and the drivers door (or any door on 
some models) is opened the sunroof ECU will disable the function of the sunroofs.
On some models the sunroof ECU will disable the sunroofs as soon as the ignition is turned 
off.
On all models the sunroofs will not operate while the ignition key is turned to the cranking 
position III. 
						

							DESCRIPTION AND OPERATION
4.24DISCOVERY SERIES II
MIRRORS
DESCRIPTION
General
The door mirrors are electrically adjustable using a joystick operated mirror switch located 
on the fascia. The mirrors only operate with the ignition switch in position II.
The mirror switch can be rotated to select the left or right hand door mirror. A central position 
on the switch isolates the mirror operation. Movement of the switch in the vertical or 
horizontal positions moves the selected mirror glass accordingly. The mirror glass is 
attached to a swash plate operated vertically and horizontally by two motors.
Each mirror glass has heater elements bonded to the rear of the glass for demisting. The 
mirror heater elements operate when the heated rear window is switched on.
OPERATION
Mirrors Supply
Circuit supply
A feed from the battery positive terminal is connected on an R wire to the engine 
compartment fusebox where it passes through fusible links 1, 6 and 8, and fuse 13.
A feed from fusible link 6 is connected to the passenger compartment fusebox on an OS 
wire. The feed passes through fuse 8 in the passenger compartment fusebox and is 
connected to the contacts of the heated rear screen relay.
A feed from fusible link 8 is connected on an NW wire to the passenger compartment 
fusebox and from the fusebox to the ignition switch on an N wire.
A feed from fuse 13 is connected to the passenger compartment fusebox on a PN wire and 
is connected to the coil of the heated rear screen relay.
Ignition switch supply
With the ignition switch in position II, the feed from fusible link 8 passes through the ignition 
switch to the passenger compartment fusebox on a W wire. The feed continues through fuse 
30 in the passenger compartment fusebox and is connected on a GLG wire to the electric 
mirror switch.
Mirrors Operation
Driver mirror adjustment
The mirror switch is connected on a B wire, via header C0760, to earth header C0017 LHD/
C0018 RHD. 
						

							DESCRIPTION AND OPERATION
DISCOVERY SERIES II 4.25
Vertical - Up
When the electric mirror switch is operated in the up position the feed from fuse 30 passes 
through the switch contacts and is connected to the mirror vertical adjustment motor. The 
wire connections are as follows:
zOn LHD vehicles, the connection from the switch is on a BK wire to the motor.
zOn RHD vehicles, the connection from the switch is on a BN wire to connector interface 
C0460-7/C0733-7. From the connector interface the connection continues to the motor 
on a BK wire.
The earth path for the motor is connected on an SW wire, via splice joint A9 and earth header 
C0285 LHD/C0292 RHD, to the mirror switch.
Vertical down
When the electric mirror switch is operated in the down position the feed from fuse 30 
passes through the switch contacts and is connected to the mirror vertical adjustment motor 
on an SW wire, via splice joint A9 and header joint C0285 LHD/C0292 RHD.
The earth path for the motor is connected as follows:
zOn LHD vehicles, the earth path is on a BK wire to the mirror switch.
zOn RHD vehicles, the earth path is on a BK wire to connector interface C0733-7/
C0460-7. From the connector interface the earth is connected to the mirror switch on 
a BN wire.
Horizontal - left
When the electric mirror switch is operated in the left position the feed from fuse 30 passes 
through the switch contacts and is connected to the mirror horizontal adjustment motor on 
an SW wire, via splice joint A9 and header joint C0285 LHD/C0292 RHD.
The earth path for the motor is connected as follows:
zOn LHD vehicles, the earth path is on a BU wire to the mirror switch.
zOn RHD vehicles, the earth path is on a BU wire to connector interface C0733-8/
C0460-8. From the connector interface the earth is connected to the mirror switch on 
a BP wire. 
						

							DESCRIPTION AND OPERATION
4.26DISCOVERY SERIES II
Horizontal - right
When the electric mirror switch is operated in the right position the feed from fuse 30 passes 
through the switch contacts and is connected to the mirror horizontal adjustment motor. The 
wire connections are as follows:
zOn LHD vehicles, the connection from the switch is on a BU wire to the motor.
zOn RHD vehicles, the connection from the switch is on a BP wire to connector interface 
C0460-8/C0733-8. From the connector interface the connection continues to the motor 
on a BU wire.
The earth path for the motor is connected on an SW wire, via splice joint A9 and earth header 
C0285 LHD/C0292 RHD, to the mirror switch.
Passenger mirror adjustment
The mirror switch is connected on a B wire, via header C0760, to earth header C0017 LHD/
C0018 RHD.
Vertical - Up
When the electric mirror switch is operated in the up position the feed from fuse 30 passes 
through the switch contacts and is connected to the mirror vertical adjustment motor. The 
wire connections are as follows:
zOn LHD vehicles, the connection from the switch is on a BN wire to connector interface 
C0464-7/C0733-7. From the connector interface the connection continues to the motor 
on a BK wire.
zOn RHD vehicles, the connection from the switch is on a BK wire to the motor.
The earth path for the motor is connected on an SW wire, via splice joint A9 and earth header 
C0285 LHD/C0292 RHD, to the mirror switch.
Vertical down
When the electric mirror switch is operated in the down position the feed from fuse 30 
passes through the switch contacts and is connected to the mirror vertical adjustment motor 
on an SW wire, via splice joint A9 and header joint C0285 LHD/C0282 RHD.
The earth path for the motor is connected as follows:
zOn LHD vehicles, the earth path is on a BK wire to connector interface C0733-7/
C0464-7. From the connector interface the earth is connected to the mirror switch on 
a BN wire.
zOn RHD vehicles, the earth path is on a BK wire to the mirror switch. 
						

							DESCRIPTION AND OPERATION
DISCOVERY SERIES II 4.27
Horizontal - left
When the electric mirror switch is operated in the left position the feed from fuse 30 passes 
through the switch contacts and is connected to the mirror horizontal adjustment motor on 
an SW wire, via splice joint A9 and header joint C0285 LHD/C0292 RHD.
The earth path for the motor is as follows:
zOn LHD vehicles, the earth path is on a BU wire to connector interface C0733-8/
C0464-8. From the connector interface the earth is connected to the mirror switch on 
a BP wire.
zOn RHD vehicles, the earth path is on a BU wire to the mirror switch.
Horizontal - right
When the electric mirror switch is operated in the right position the feed from fuse 30 passes 
through the switch contacts and is connected to the mirror horizontal adjustment motor. The 
wire connections are as follows:
zOn LHD vehicles, the connection from the switch is on a BP wire to connector interface 
C0464-8/C0733-8. From the connector interface the connection continues to the motor 
on a BU wire.
zOn RHD vehicles, the connection from the switch is on a BU wire to the motor.
Mirror heater
The LH and RH door mirror heaters are connected from the heated rear screen relay in the 
passenger compartment fusebox on an NP wire via splice joints A19/A167.
When the heated rear window switch is operated an earth path is completed from the switch 
on a B wire, via header C0760, to earth header C0017 LHD/C0018 RHD. The switch is 
connected on an NB wire to pin C0663-5 on the BCU.
On vehicles with Air Temperature Control (ATC), when the demist function is selected the 
ATC ECU provides an earth path on an NB wire through splice joint A249, to pin C0663-5 
on the BCU.
The completed earth path is interpreted by the BCU as a signal for heated rear screen 
operation. The BCU is connected from pin C0661-1 on an SK wire to the the IDM in the 
passenger compartment fusebox. The SK wire is the serial data bus between the BCU and 
the IDM. The BCU passes a signal to the IDM which in turn provides an earth path, on a B 
wire to earth header C0551, for the coil of the heated rear screen relay in the passenger 
compartment fusebox. 
						

							DESCRIPTION AND OPERATION
4.28DISCOVERY SERIES II
The heated rear screen relay coil is energised by the feed from fuse 13 in the engine 
compartment fusebox causing the relay contacts to close. With the contacts closed, a feed 
from fuse 8 in the passenger compartment fusebox passes through the relay and is 
connected from the fusebox on an NP wire to splice joints A19/A167. From the splice joints 
the feed is connected on NP wires to the driver and passenger door mirror heaters.
On LHD vehicles, the driver’s door mirror heater is connected on a B wire, via splice joint 
A34 and header C0288, to earth header C0017. The passenger door mirror heater is 
connected on a B wire, via splice joint A34, to earth header C0018.
On RHD vehicles, the driver’s door mirror heater is connected on a B wire, via splice joint 
A34, to earth header C0018. The passenger door mirror is connected on a B wire, via splice 
joint A34, to earth header C0017.
The door mirror heaters will operate for as long as the heated rear screen relay is energised. 
						

							DESCRIPTION AND OPERATION
DISCOVERY SERIES II 4.29
FOLDING MIRRORS (JAPAN ONLY)
DESCRIPTION
Folding Mirrors (Japan only)
The door mirrors can be folded electrically to prevent damage using the joystick operated 
mirror switch located on the fascia. The mirrors only operate with the ignition switch in 
position II.
The central position on the switch is used for the folding mirrors function. The switch is 
moved vertically down to fold the mirrors in or out. A dedicated folding mirrors ECU is located 
behind the fascia adjacent to the A post. All feeds to and from the folding mirror motors are 
controlled by the ECU.
Folding mirror operation is controlled by an earth signal received by the ECU from the mirror 
switch. The ECU supplies a feed to each motor to drive it in the required direction. The feed 
is supplied for a maximum of 30 seconds. The motors detect a stall condition when they are 
fully folded in or out which is sensed by the ECU which then removes the power feed.
OPERATION
Folding Mirrors Supply
Circuit supply
A feed from the battery positive terminal is connected on an R wire to to the engine 
compartment fusebox, where it passes through fusible links 3 and 8.
A feed from fusible link 3 is connected on an NR wire to the passenger compartment fusebox 
where it passes through fuse 21. The feed is connected from fuse 21 on a PB wire to header 
C0292. From the header the feed is connected on an NS wire to pin C0907-8 on the folding 
mirror ECU.
A feed from fusible link 8 is connected from the engine compartment fusebox on an NW wire 
to the passenger compartment fuse box. The passenger compartment fusebox is connected 
to the ignition switch on an N wire.
Ignition switch supply
With the ignition switch in position II, the feed from fusible link 8 flows through the ignition 
switch to the passenger compartment fusebox on a W wire where it passes through fuse 31. 
From fuse 31 the feed is connected on a GR wire from the fusebox, via header C0289, to 
pin C0907-6 on the folding mirror ECU. The ECU is connected on a B wire to earth header 
C0017.