LAND ROVER DISCOVERY 1999 Workshop Manual

ALARM SYSTEM AND HORN
86-4-28 REPAIR
Receiver - alarm system - models with
sunroof
$% 86.77.31
Remove
1.Remove trim seal from rear sunroof.
2.Release sunroof switch and remove screw
securing headlining.
3.Remove 2 nuts securing receiver to roof panel,
disconnect multiplug and remove receiver.
Refit
1.Connect multiplug to receiver, fit to roof panel,
tighten nuts to 10 Nm (7 lbf.ft).
2.Fit and tighten screw securing headlining.
3.Fit sunroof switch
4.Fit sunroof trim seal.
5.Connect multiplug to receiver, fit to roof panel
and secure with nuts tighten to 10 Nm (7 lbf.ft).
Receiver - alarm system - models
without sunroof
$% 86.77.31
Remove
1.Remove rear headrest. Repeat operation on
opposite side.

+ SEATS, REPAIRS, Head restraint -
third row seat.
2.Remove 'D' post trim casing. Repeat operation
on opposite side.

+ INTERIOR TRIM COMPONENTS,
REPAIRS, Trim casing - 'D' post.
3.Remove rear interior light.

+ LIGHTING, REPAIRS, Lamp - interior
- rear.
4.Release 2 studs securing rear headlining,
carefully lower lining.
5.Remove 2 studs securing alarm receiver.
6.Disconnect multiplug from alarm receiver and
remove receiver.
Refit
1.Connect multiplug to receiver.
2.Position receiver and secure with studs.
3.Position rear end of headlining, secure with
studs.
4.Fit rear interior light.

+ LIGHTING, REPAIRS, Lamp - interior
- rear.
5.Fit both 'D' post trim casings. Repeat operation
on opposite side.

+ INTERIOR TRIM COMPONENTS,
REPAIRS, Trim casing - 'D' post.
6. Fit rear headrests. Repeat operation on
opposite side.

+ SEATS, REPAIRS, Head restraint -
third row seat.
M86 5632
M86 5761

ALARM SYSTEM AND HORN
REPAIR 86-4-29
Coil - passive immobilisation
$% 86.77.35
Remove
1.Remove steering column nacelle.

+ STEERING, REPAIRS, Nacelle -
steering column.
2.Release passive coil from steering lock.
3.Disconnect illumination bulb holder and
multiplug and remove passive coil.
Refit
1.Position passive coil, connect multiplug and
illumination bulb holder.
2.Fit passive coil to steering lock.
3.Fit steering column nacelle.

+ STEERING, REPAIRS, Nacelle -
steering column.

WINDOWS
DESCRIPTION AND OPERATION 86-5-1
WINDOWS DESCRIPTION AND OPERAT ION
Electric windows block diagram
1Passenger compartment fusebox
2BCU
3LH front window switch
4LH front window motor
5RH front window switch
6RH front window motor
7Rear window lift relay8Centre console LH rear window switch
9LH rear door window switch
10LH rear door window motor
11Centre console RH rear window switch
12RH rear door window switch
13RH rear door window motor
14Rear window isolation switch

WINDOWS
86-5-2 DESCRIPTION AND OPERATION
Electric windows component layout
RHD shown, LHD similar

WINDOWS
DESCRIPTION AND OPERATION 86-5-3
1Passenger compartment fusebox
2Body Control Unit (BCU)
3LH front window switch
4LH front window motor
5RH front window switch
6RH front window motor
7Rear window lift relay
8Centre console LH rear window switch
9LH rear door window switch
10LH rear door window motor
11Centre console RH rear window switch
12RH rear door window switch
13RH rear door window motor
14Rear window isolation switch

WINDOWS
86-5-4 DESCRIPTION AND OPERATION
Description
Body Control Unit (BCU)
RHD shown, LHD similar
The BCU controls all operations for the front windows. It controls the voltage and the earth paths to the window
motors, it controls one-touch down operation and it detects stall conditions. Stall detection protects the system from
sustained high current draw that occurs when a window reaches the fully up/down position or becomes stuck. When
the BCU detects a stall condition, it disables operation at the stalled window until the window switch is released. Upon
releasing the window switch, the BCU allows normal window operation.
The BCU receives power from fuse 34 (30A) of the passenger compartment fusebox. There is a unique earth signal
between each pole of the front window switches and the BCU. This allows the BCU to determine which window motor
to operate as well as which direction to operate the motor. The BCU operates the front window motors directly. There
are no relays or switches between the BCU and the window motors.
The BCU disables stall detection on the front windows for a period of 500 ms when an electric window operates to
allow for initial current surge to the window motor. After this period, if the BCU detects a stall signal (high current draw)
for more than 300 ms, it disables the window motor until the window switch is released.
The BCU also contains the ignition switched off timeout information for both the front and the rear windows. It controls
the rear window timeout function through the IDM.
TestBook communicates with the BCU and can determine the status of the front window switches. TestBook can also
operate both front windows. TestBook can only determine rear window timeout status. It cannot determine the status
of the rear windows, nor can it operate the rear windows.
Do not feed TestBook cables through open windows as the windows operate while performing test.

WINDOWS
DESCRIPTION AND OPERATION 86-5-5
Front window switches
The front window switches are non-latching rocker switches located in the center console. The front window switches
contain illumination bulbs that operate when the side lamps or headlamps are on.
The front window switches provide earth signals to the BCU. The BCU determines which direction to operate the front
window motors.
TestBook will monitor the real time status of the front window switches.

WINDOWS
86-5-6 DESCRIPTION AND OPERATION
Front window motors
The front window motors are permanent magnet motors. There is a window motor in each front door. The front
window motors are controlled by the BCU.
The BCU provides both the voltage and the earth paths to the front window motors. The BCU reverses the direction
the window motor operates by switching the voltage and earth paths to the window motor. The BCU also monitors
stall current for the front window motors.
TestBook can operate the front window motors remotely.

WINDOWS
DESCRIPTION AND OPERATION 86-5-7
Rear window lift relay
The rear window lift relay is a normally open relay that provides power to the rear window system. It is controlled by
the IDM. The IDM receives a rear window enable signal from the BCU to allow operation during the ignition switched-
off timeout period.
Both the rear window lift relay and the IDM are located in the passenger compartment fusebox. The IDM is integral
to the passenger compartment fusebox.
The rear window lift relay receives voltage from fuse 13 (30A) in the passenger compartment fusebox. The IDM
controls the earth side of the relay coil.
TestBook cannot monitor the status of the rear window lift relay.