Discovery electrical Manual - part 25

DATA LINK CONNECTOR

D3

2

CIRCUIT DIAGRAM

7

S2108

14

C217

WLG

With ABS

Z108
Anti–Lock Brake
System ECU

X318
Data Link Con-
nector (OBDII)

15

C2083

WK

WLG

WK

S2114

13

C2084

14

WLG

WK

Without ABS

With ABS

Without ABS

15

14

C217

Not used

Z132
Engine Control
Module (ECM)

27

C243

42

WLG

WK

15

300Tdi with EDC

MFI–T16

14

C217

15

MFI–V8

Not used

2

C1026

Z132
Engine Control
Module (ECM)

20

C1017

23

1

SFI–V8

300Tdi without
EDC

CIRCUIT OPERATION

Speedometer

The Vehicle Speed Sensor (X190) sends a signal to
the speedometer in the form of voltage pulses.  The
pulses are filtered by a Vehicle Speed Sensor Buffer
inside the speedometer.  The voltage alternates
between battery voltage and 0 volts 6 times per
wheel revolution.  The speed sensor signal is also
sent to the Cruise Control ECU (Z121), Multifunction
Unit (MFU) (Z148) (Persian Gulf States), and the
Engine Control Module (Z132).

Tachometer

The tachometer displays engine speed in rpm.
Voltage pulses are taken from the Generator (Z106)
and are generated when the engine drive belt turns
the Generator pulley.  The tachometer responds to
the frequency of the voltage pulses, which increases
proportionally to that of the engine speed.

Engine Coolant Temperature Gauge

The Engine Coolant Temperature Sensor (X114) has
approximately 136 ohms resistance when the coolant
temperature is low.  As coolant temperature
increases, the resistance of the sensor decreases.
This varying resistance causes the current through
the sensor to change and the gauge to register the
temperature.  When the coolant is hot, the resistance
of the sensor is approximately 17 ohms.

Fuel Gauge

When the fuel tank level is low, the resistance of the
fuel gauge sender is approximately 245 ohms.  As the
fuel level increases, the resistance of the sender
decreases, causing the gauge to register the change.
When the fuel tank is full, the resistance of the sender
is approximately 19 ohms.  When the fuel gauge
sender’

s resistance falls below approximately 25

ohms (6 liters/1.5 US gallons), the fuel warning light
will illuminate to warn the driver .

INSTRUMENTS

E1

1

CIRCUIT OPERATION

INSTRUMENTS

E1

2

CIRCUIT DIAGRAM

1

C370

See Fuse Details

See Fuse Details

15

C208

20

C204

3

C370

BR

2

C105

5

C209

2

C221

LG

S2049

S214

2

C222

P126
Fascia Fuse Box

X190
Vehicle Speed
Sensor

4

C221

YK

15

F 14
10 A

[1]

[12]

[11]

A

E1-3

S344

GY

1

B

S253

HJ8

See Ground Dis-
tribution

E201

17

C209

Instruments

Warnings and
Indicators

31

15

HJ9

Z142
Instrument
Cluster

[1]

Speedome-
ter

[11] Vehicle

Speed Input

[12] Vehicle

Speed Out-
put

INSTRUMENTS

E1

3

CIRCUIT DIAGRAM

A

E1-2

S2030

6

C243

Z132
Engine Control
Module (ECM)

29

C243

Z132
Engine Control
Module (ECM)

Not used

MFI–V8

300Tdi without
EDC

MFI–T16

300Tdi with EDC

12

C217

YK

Z132
Engine Control
Module (ECM)

11

C284

Z121
Cruise Control
ECU

27

C1017

HJ2

S2030

HJ2

Except NAS

NAS

YK

5

C1027

87

C2106

Z126
Service Re-
minder Unit

11

C284

Z121
Cruise Control
ECU

1

C2062

14

C205

Z148
Multi–Function
Unit (MFU)

Y

X241
Saudi Junction
Connector

1

C2062

Y

YK