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

DESCRIPTION AND OPERATION
4.80DISCOVERY SERIES II
Power relay
The coil of the power relay receives a feed from fuse 31 in the passenger compartment 
fusebox. The feed passes on a GK wire to splice joint A9/A144. From the splice joint the feed 
passes on a GR wire to connector interface C0765-1/C0778-1. From the connector interface 
the feed passes, via splice joint A1, to the coil of the power relay. The coil is connected to 
pin C0793-10 on the ATC ECU.
The power relay operates speed 31 of the blower...

DESCRIPTION AND OPERATION
DISCOVERY SERIES II 4.81
In-car temperature sensor
The in-car temperature sensor receives a feed from fuse 31 in the passenger compartment 
fusebox. The feed passes on a GK wire to splice joint A9/A144. From the splice joint the feed 
passes on a GR wire to the in-car temperature sensor and is connected to a motor which 
draws air over the sensor. The motor is connected on a B wire from the in-car temperature 
sensor, via header C0760, to earth header C0017 LHD/C0018 RHD.
A...

DESCRIPTION AND OPERATION
4.82DISCOVERY SERIES II
Air temperature mode motor – RH
A reference voltage from the ATC ECU pin C0791-8 is connected on a BW wire, via splice 
joints A145/A145, A26, B26 and C26 to the RH air temperature mode motor.
A reference voltage from the ATC ECU pin C0791-3 is connected on a GW wire to splice 
joint A278. From the splice joint the reference voltage continues on a GR wire, through splice 
joint A22 and B22 to the RH air temperature mode motor.
An input from the RH air...

DESCRIPTION AND OPERATION
DISCOVERY SERIES II 4.83
When the rear air conditioning switch is operated, the rear blower relay coil is energised, 
closing the relay contacts. This allows the feed from fusible link 4 in the engine compartment 
fusebox to pass through the relay to operate the rear blower motor on an NR wire.
Rear air conditioning switch
When the rear A/C switch is operated, an earth path is completed from the switch on a BR 
wire to the rear blower switch. The completion of the earth path...

DESCRIPTION AND OPERATION
4.84DISCOVERY SERIES II
HEATER BLOWER - FRESH/RECIRCULATED AIR MOTOR (NON A/C 
VEHICLES)
DESCRIPTION
General
The heater blower is operated from a four position linear switch located in the centre of the 
fascia on the heater control panel. The blower motor only operates with the ignition switch 
in position II. The blower motor control switch is illuminated when the side lights are turned 
on.
The blower motor is located in the air inlet duct. A resistor pack is located on the...

DESCRIPTION AND OPERATION
DISCOVERY SERIES II 4.85
Ignition switch supply
When the ignition switch is 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 GK wire to splice joint A240.
From the splice joint A240 the feed is connected on a GK wire to the fresh recirculated air 
switch.
From the splice joint A240, the feed is also connected on a GR to splice...

DESCRIPTION AND OPERATION
4.86DISCOVERY SERIES II
With the blower motor switch in position 4, the earth path for the blower motor is direct to the 
blower motor switch on a BO wire via splice joint A1 and operates the blower motor at fast 
speed. The blower motor switch is connected on a B wire, via splice joint A7, to earth eyelet 
connector C0910-1.
Fresh/Recirculated Air Operation
The fresh/recirculated air mode motor can only operate when the ignition switch is in position 
II. The feed from fuse 31...

DESCRIPTION AND OPERATION
DISCOVERY SERIES II 4.87
FUEL BURNING HEATER (FBH) - Td5 ONLY
DESCRIPTION
General
The FBH system is an optional auxiliary heating system that compensates for relatively low 
coolant temperatures inherent in Diesel engines. At low ambient temperatures, the FBH 
system heats the coolant supply to the heater matrix and maintains it at a temperature for 
good in-car heating performance. FBH operation is fully automatic with no driver intervention 
required.
The system comprises an...

DESCRIPTION AND OPERATION
4.88DISCOVERY SERIES II
A feed from fuse 9 in the engine compartment fusebox is connected on a PN wire to the FBH 
unit. When the FBH unit senses the voltage from the air temperature sensor, internal 
circuitry in the FBH unit allows the feed from fuse 9 to activate the FBH. The FBH unit is 
connected on a B wire to earth header C0018 LHD/C0017 RHD.
The FBH unit supplies a feed on a WU wire to the FBH pump. The feed operates the FBH 
pump which is connected on a B wire to earth...

DESCRIPTION AND OPERATION
DISCOVERY SERIES II 4.89
COOLING FAN
DESCRIPTION
General
The cooling fan is located on brackets forward of the radiator. The fan motor is operated by 
a cooling fan relay controlled by the Engine Control Module (ECM). The main relay supplies 
a feed to the coil of the cooling fan relay. A permanent feed is supplied to the coils of the 
main and cooling fan relays located in the engine compartment fusebox. On V8 models a 
coolant temperature sensor is located in the inlet...