Ford Mondeo (petrol engines). Manual - part 117

Chapter 12 Body electrical system

Air bag clock spring - removal and refitting  . . . . . . . . . . . . . . . . . . . 30
Air bag control module - removal and refitting  . . . . . . . . . . . . . . . . . 29
Air bag unit (driver’s side) - removal and refitting  . . . . . . . . . . . . . . . 28
Anti-theft alarm system - general information . . . . . . . . . . . . . . . . . . 20
Auxiliary warning system - general information and 

component renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Battery - check, maintenance and charging  . . . . . . . .

See Chapter 1

Battery - removal and refitting  . . . . . . . . . . . . . . . . . . .

See Chapter 5

Bulbs (exterior lights) - renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5

Bulbs (interior lights) - renewal  . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6

Clock - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Compact disc player - removal and refitting . . . . . . . . . . . . . . . . . . . 25
Cruise control system - general information  . . . . . . . . . . . . . . . . . . . 21
Electrical fault finding - general information  . . . . . . . . . . . . . . . . . . .

2

Electrical system check  . . . . . . . . . . . . . . . . . . . . . . . .

See Chapter 1

Exterior light units - removal and refitting  . . . . . . . . . . . . . . . . . . . . .

7

Fuses, relays and timer module - testing and renewal  . . . . . . . . . . .

3

General information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1

Headlight beam alignment - checking and adjustment  . . . . . . . . . .

8

Headlight levelling motor - removal and refitting  . . . . . . . . . . . . . . .

9

Horn - removal and refitting  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Instrument panel - removal and refitting  . . . . . . . . . . . . . . . . . . . . . . 10
Instrument panel components - removal and refitting  . . . . . . . . . . . 11
Radio aerial - removal and refitting  . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Radio/cassette player - coding, removal and refitting  . . . . . . . . . . . 23
Radio/cassette player power amplifier - removal and refitting  . . . . . 24
Speakers - removal and refitting  . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Speedometer drive cable - removal and refitting  . . . . . . . . . . . . . . . 12
Stop-light switch - removal and refitting  . . . . . . . . . . .

See Chapter 9

Switches - removal and refitting  . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4

Tailgate wiper motor assembly - removal and refitting  . . . . . . . . . . . 17
TCS inhibition switch - removal and refitting  . . . . . . . .

See Chapter 9

Trip computer module - removal and refitting  . . . . . . . . . . . . . . . . . 18
Windscreen/tailgate washer system and wiper blade 

check  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

See Chapter 1

Windscreen/tailgate washer system components - removal 

and refitting  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Windscreen wiper motor and linkage - removal and refitting  . . . . . . 16
Wiper arms - removal and refitting  . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Fuses (auxiliary fusebox in engine compartment)

Note: Fuse ratings and circuits are liable to change from year to year. Consult the handbook supplied with the vehicle, or consult a Ford dealer,
for specific information.

Fuse No

Rating

Colour

Circuit(s) protected

1

80

Black  . . . . . . . . . . . . . . . . . . . . . . . . . .

Power supply to main fusebox

2

60

Yellow  . . . . . . . . . . . . . . . . . . . . . . . . .

Radiator electric cooling fans

3

60

Yellow  . . . . . . . . . . . . . . . . . . . . . . . . .

Diesel engine glow plugs and/or ABS braking system

4

20

Yellow  . . . . . . . . . . . . . . . . . . . . . . . . .

Ignition system, or ignition and daytime running lights

5

30

Light green . . . . . . . . . . . . . . . . . . . . . .

Heated windscreen (left-hand side)

6

30

Light green . . . . . . . . . . . . . . . . . . . . . .

Heated windscreen (right-hand side)

7

30

Light green . . . . . . . . . . . . . . . . . . . . . .

ABS braking system

8

30

Light green . . . . . . . . . . . . . . . . . . . . . .

Air conditioning compressor/heated seats or air conditioning
compressor/daytime running lights

9

20

Light blue  . . . . . . . . . . . . . . . . . . . . . . .

ECU (petrol), Cold start solenoid (Diesel)

10

20

Light blue  . . . . . . . . . . . . . . . . . . . . . . .

Ignition switch

11

3

Violet  . . . . . . . . . . . . . . . . . . . . . . . . . .

ECU memory

12

15

Light blue  . . . . . . . . . . . . . . . . . . . . . . .

Horn and hazard flasher warning system

13

15

Light blue  . . . . . . . . . . . . . . . . . . . . . . .

Oxygen sensor

14

15

Light blue  . . . . . . . . . . . . . . . . . . . . . . .

Fuel pump

15

10

Red  . . . . . . . . . . . . . . . . . . . . . . . . . . .

Dipped beam headlight (right-hand side)

16

10

Red  . . . . . . . . . . . . . . . . . . . . . . . . . . .

Dipped beam headlight (left-hand side)

17

10

Red  . . . . . . . . . . . . . . . . . . . . . . . . . . .

Main beam headlight (right-hand side)

18

10

Red  . . . . . . . . . . . . . . . . . . . . . . . . . . .

Main beam headlight (left-hand side)

12•1

Easy, suitable for
novice with little
experience

Fairly easy, suitable
for beginner with
some experience

Fairly difficult, suitable
for competent DIY
mechanic

Difficult, suitable for
experienced  DIY
mechanic

Very difficult,
suitable for expert DIY
or  professional

Degrees of difficulty

Specifications

Contents

12

Fuses (main fusebox in passenger compartment)

Note: Fuse ratings and circuits are liable to change from year to year. Consult the handbook supplied with the vehicle, or consult a Ford dealer,
for specific information.
Fuse

Rating

Colour

Circuit(s) protected

19

7.5

Brown  . . . . . . . . . . . . . . . . . . . . . . . . .

Heated door mirrors

20

10

Black  . . . . . . . . . . . . . . . . . . . . . . . . . .

Front/rear wiper motor (circuit breaker)

21

30

Light green . . . . . . . . . . . . . . . . . . . . . .

Front electric windows (only)

21

40

Orange  . . . . . . . . . . . . . . . . . . . . . . . . .

Front and rear electric windows

22

7.5

Brown  . . . . . . . . . . . . . . . . . . . . . . . . .

ABS module

23

15

Light blue  . . . . . . . . . . . . . . . . . . . . . . .

Reversing lights

24

15

Light blue  . . . . . . . . . . . . . . . . . . . . . . .

Stop-lights

25

20

Yellow  . . . . . . . . . . . . . . . . . . . . . . . . .

Central locking system/double-locking/anti-theft alarm

26

20

Yellow  . . . . . . . . . . . . . . . . . . . . . . . . .

Foglights

27

15

Light blue  . . . . . . . . . . . . . . . . . . . . . . .

Cigar lighter

28

30

Light green . . . . . . . . . . . . . . . . . . . . . .

Headlight washer system

29

30

Light green . . . . . . . . . . . . . . . . . . . . . .

Heated rear window

30

7.5

Brown  . . . . . . . . . . . . . . . . . . . . . . . . .

Interior lighting and auxiliary warning system

31

7.5

Brown  . . . . . . . . . . . . . . . . . . . . . . . . .

Instrument panel illumination

32

7.5

Brown  . . . . . . . . . . . . . . . . . . . . . . . . .

Radio

33

7.5

Brown  . . . . . . . . . . . . . . . . . . . . . . . . .

Front and rear sidelights (left-hand side)

34

7.5

Brown  . . . . . . . . . . . . . . . . . . . . . . . . .

Interior lighting and digital clock

35

7.5

Brown  . . . . . . . . . . . . . . . . . . . . . . . . .

Front and rear sidelights (right-hand side)

36

30

Light green . . . . . . . . . . . . . . . . . . . . . .

Air bag

37

30

Light green . . . . . . . . . . . . . . . . . . . . . .

Heater blower

38

7.5

Brown  . . . . . . . . . . . . . . . . . . . . . . . . .

Adaptive damping

Relays (auxiliary fusebox in engine compartment)

Relay

Colour

Circuit(s) protected

R1

Green . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Daytime running lights (left-hand-drive, but not all countries) or dim-
dip lights (UK)

R2

Black  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Radiator electric cooling fan (high speed)

R3

Blue (petrol)  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Air conditioning cut-out

R3

Brown (Diesel)  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Air conditioning in conjunction with Diesel engine

R4

Yellow  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Windscreen heater time delay 

R5

Dark green (petrol) . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Radiator electric cooling fan (low speed)

R5

Black (Diesel) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Radiator electric cooling fan (low speed)

R6

Yellow  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Starter solenoid

R7

Brown  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Horns

R8

Brown  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Fuel pump

R9

White  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Dipped beam headlights

R10

White  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Main beam headlights

R11

Brown  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

ECU power supply (petrol), cold start (Diesel)

Relays (main fusebox in passenger compartment)

Relay

Colour

Circuit(s) protected

R12

White  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Interior, courtesy and footwell lights

R13

Yellow  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Heated rear window

R14

Yellow  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Heater blower

R15

Green . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Windscreen wiper motor

R16

Black  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Ignition

Auxiliary relays (not in the fuseboxes)

Relay

Colour

Circuit(s) protected

Location

R17

Black  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Diesel glow plug

Battery tray

R18

Black  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

“One-touch down” 

Driver’s door

 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

driver’s window relay

R19

Blue  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Speed control cut-off

Central fuse box bracket the 
below instrument panel

R20

Blue  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Headlight washer system

Bulb module bracket

R21

Orange . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Rear screen wiper interval

Bulb module bracket

R22

White  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Foglights (left-hand-drive only)

Interface module bracket

R23

Black  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Direction indicators

Steering column

R24

White  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Anti-theft alarm (left-hand side)

Door lock module bracket

R25

White  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Anti-theft alarm (right-hand side)

Door lock module bracket

R26

Black  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Heated seats

Door lock module bracket

12•2 Body electrical system

Bulbs

Wattage

Type

Headlight main beam  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

55

Halogen

Headlight dipped beam . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

55

Halogen

Foglights  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

55

Halogen

Sidelights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5

Wedge

Direction indicator lights  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

21

Bayonet

Side repeater lights  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5

Wedge

Stop-lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

21

Bayonet

Reversing lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

21

Bayonet

Rear fog/tail lights (Saloon and Estate)  . . . . . . . . . . . . . . . . . . . . . . . . . .

21/4

Bayonet

Rear tail light (Saloon and Hatchback)  . . . . . . . . . . . . . . . . . . . . . . . . . .

5

Bayonet

Number plate lights  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5

Festoon

Engine compartment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

10

Wedge

Interior lights  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

10

Festoon

Reading light  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5

Wedge

Torque wrench settings

Nm

lbf ft

Windscreen wiper motor bolts:

Into old motor (see text)  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

8

6

Into new motor (see text) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

12

9

Body electrical system  12•3

12

Warning: Before carrying out any
work on the electrical system,
read through the precautions

given in “Safety first!” at the beginning of
this manual.

The electrical system is of 12-volt negative

earth type. Power for the lights and all
electrical accessories is supplied by a
lead/acid battery which is charged by the
alternator.

This Chapter covers repair and service

procedures for the various electrical
components not associated with the engine.
Information on the battery, ignition system,

alternator, and starter motor can be found in
Chapter 5.

All models are fitted with a driver’s air bag,

which is designed to prevent serious chest
and head injuries to the driver during an
accident. A similar bag for the front seat
passenger is also available (see illustration).
The sensor and electronic unit for the air bag
is located next to the steering column inside
the vehicle, and contains a back-up capacitor,
crash sensor, decelerometer, safety sensor,
integrated circuit and microprocessor (see
illustration). The air bag is inflated by a gas
generator, which forces the bag out of the
module cover in the centre of the steering
wheel. A “clock spring” ensures that a good
electrical connection is maintained with the air
bag at all times - as the steering wheel is
turned in each direction, the spring winds and
unwinds.

All UK models are fitted with an alarm

system incorporating a movement sensor and
ignition immobiliser. On Saloon and
Hatchback models, the alarm system horn is
located on the left-hand side of the luggage

1 General information

1.3A  Air bag system components

1  Air bag module (driver’s)
2  Clock spring

3  Diagnostic and sensor unit
4  Air bag indicator light

5  Air bag module 

(passenger’s)

1.3B  Air bag sensor and electronic unit

1  Crash sensor
2  Safety sensor
3  Voltage back-up
4  Application Specific Integrated Circuit
5  Microprocessor

compartment, but on Estate models, it is on
the right-hand side.

Some models are fitted with a headlight

levelling system, which is controlled by a knob
on the facia. On position “0”, the headlights
are in their base position, and on position “5”,
the headlights are in their maximum inclined
angle.

It should be noted that, when portions of

the electrical system are serviced, the cable
should be disconnected from the battery
negative terminal, to prevent electrical shorts
and fires.

Caution: When disconnecting the
battery for work described in the
following Sections, refer to
Chapter 5, Section 1.

Note: Refer to the precautions given in
“Safety first!” and in Section 1 of this Chapter
before starting work. The following tests relate
to testing of the main electrical circuits, and
should not be used to test delicate electronic
circuits (such as engine management systems,
anti-lock braking systems, etc), particularly
where an electronic control module is used.
Also refer to the precautions given in Chapter
5, Section 1.

General

1 A typical electrical circuit consists of an
electrical component, any switches, relays,
motors, fuses, fusible links or circuit breakers
related to that component, and the wiring and
connectors which link the component to both
the battery and the chassis. To help to
pinpoint a problem in an electrical circuit,
wiring diagrams are included at the end of this
manual.
2 Before attempting to diagnose an electrical
fault, first study the appropriate wiring
diagram, to obtain a complete understanding
of the components included in the particular
circuit concerned. The possible sources of a
fault can be narrowed down by noting if other
components related to the circuit are
operating properly. If several components or
circuits fail at one time, the problem is likely to
be related to a shared fuse or earth
connection.
3 Electrical problems usually stem from
simple causes, such as loose or corroded
connections, a faulty earth connection, a
blown fuse, a melted fusible link, or a faulty
relay (refer to Section 3 for details of testing
relays). Visually inspect the condition of all
fuses, wires and connections in a problem
circuit before testing the components. Use
the wiring diagrams to determine which
terminal connections will need to be checked
in order to pinpoint the trouble-spot.
4 The basic tools required for electrical fault-
finding include a circuit tester or voltmeter (a
12-volt bulb with a set of test leads can also

be used for certain tests); an ohmmeter (to
measure resistance and check for continuity);
a battery and set of test leads; and a jumper
wire, preferably with a circuit breaker or fuse
incorporated, which can be used to bypass
suspect wires or electrical components.
Before attempting to locate a problem with
test instruments, use the wiring diagram to
determine where to make the connections.
5 To find the source of an intermittent wiring
fault (usually due to a poor or dirty
connection, or damaged wiring insulation), a
“wiggle” test can be performed on the wiring.
This involves wiggling the wiring by hand to
see if the fault occurs as the wiring is moved.
It should be possible to narrow down the
source of the fault to a particular section of
wiring. This method of testing can be used in
conjunction with any of the tests described in
the following sub-Sections.
6 Apart from problems due to poor
connections, two basic types of fault can
occur in an electrical circuit - open-circuit, or
short-circuit.
7 Open-circuit faults are caused by a break
somewhere in the circuit, which prevents
current from flowing. An open-circuit fault will
prevent a component from working.
8 Short-circuit faults are caused by a “short”
somewhere in the circuit, which allows the
current flowing in the circuit to “escape” along
an alternative route, usually to earth. Short-
circuit faults are normally caused by a
breakdown in wiring insulation, which allows a
feed wire to touch either another wire, or an
earthed component such as the bodyshell. A
short-circuit fault will normally cause the
relevant circuit fuse to blow.

Finding an open-circuit

9 To check for an open-circuit, connect one
lead of a circuit tester or the negative lead of a
voltmeter either to the battery negative
terminal or to a known good earth.
10 Connect the other lead to a connector in
the circuit being tested, preferably nearest to
the battery or fuse. At this point, battery
voltage should be present, unless the lead
from the battery or the fuse itself is faulty
(bearing in mind that some circuits are live
only when the ignition switch is moved to a
particular position).
11 Switch on the circuit, then connect the
tester lead to the connector nearest the circuit
switch on the component side.
12 If voltage is present (indicated either by
the tester bulb lighting or a voltmeter reading,
as applicable), this means that the section of
the circuit between the relevant connector
and the switch is problem-free.
13 Continue to check the remainder of the
circuit in the same fashion.
14 When a point is reached at which no
voltage is present, the problem must lie
between that point and the previous test point
with voltage. Most problems can be traced to
a broken, corroded or loose connection.

Finding a short-circuit

15 To check for a short-circuit, first
disconnect the load(s) from the circuit (loads
are the components which draw current from
a circuit, such as bulbs, motors, heating
elements, etc).
16 Remove the relevant fuse from the circuit,
and connect a circuit tester or voltmeter to the
fuse connections.
17 Switch on the circuit, bearing in mind that
some circuits are live only when the ignition
switch is moved to a particular position.
18 If voltage is present (indicated either by
the tester bulb lighting or a voltmeter reading,
as applicable), this means that there is a
short-circuit.
19 If no voltage is present during this test,
but the fuse still blows with the load(s)
reconnected, this indicates an internal fault in
the load(s).

Finding an earth fault

20 The battery negative terminal is
connected to “earth” - the metal of the
engine/transmission unit and the vehicle body
- and many systems are wired so that they
only receive a positive feed, the current
returning via the metal of the car body. This
means that the component mounting and the
body form part of that circuit. Loose or
corroded mountings can therefore cause a
range of electrical faults, ranging from total
failure of a circuit, to a puzzling partial failure.
In particular, lights may shine dimly (especially
when another circuit sharing the same earth
point is in operation), motors (eg wiper motors
or the radiator cooling fan motor) may run
slowly, and the operation of one circuit may
have an apparently-unrelated effect on
another. Note that on many vehicles, earth
straps are used between certain components,
such as the engine/transmission and the
body, usually where there is no metal-to-
metal contact between components, due to
flexible rubber mountings, etc.
21 To check whether a component is
properly earthed, disconnect the battery (refer
to Chapter 5, Section 1) and connect one lead
of an ohmmeter to a known good earth point.
Connect the other lead to the wire or earth
connection being tested. The resistance
reading should be zero; if not, check the
connection as follows.
22 If an earth connection is thought to be
faulty, dismantle the connection, and clean
both the bodyshell and the wire terminal (or
the component earth connection mating
surface) back to bare metal. Be careful to
remove all traces of dirt and corrosion, then
use a knife to trim away any paint, so that a
clean metal-to-metal joint is made. On
reassembly, tighten the joint fasteners
securely; if a wire terminal is being refitted,
use serrated washers between the terminal
and the bodyshell, to ensure a clean and
secure connection. When the connection is

2 Electrical fault finding -

general information

12•4 Body electrical system