
Chapter 13
Body electrical system
Anti-theft alarm system components - removal and refitting . . . . . .36
Auxiliary warning system components - testing, removal and
refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27
Central locking motor - removal and refitting . . . . . . . . . . . . . . . . . .17
Cigarette lighter - removal and refitting . . . . . . . . . . . . . . . . . . . . . .10
Clock - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
Electrical fault-finding - general information . . . . . . . . . . . . . . . . . . .2
Exterior lights - bulb renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
Exterior light units - removal and refitting . . . . . . . . . . . . . . . . . . . . .4
Fuel computer components - removal and refitting . . . . . . . . . . . . .26
Fuses, relays and control units - removal and refitting . . . . . . . . . .16
General information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
Headlight beam alignment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
Heater blower motor - removal and refitting . . . . . . . . . . . . . . . . . .29
Horn - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
Horn switch plate, slip rings and brushes - removal and refitting . .12
Ignition/starter switch - removal and refitting . . . . . . . . . . . . . . . . . .14
Instrument cluster - dismantling and reassembly . . . . . . . . . . . . . . .8
Instrument cluster - removal and refitting . . . . . . . . . . . . . . . . . . . . .7
Interior lights - bulb renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6Joystick fader control - removal and refitting . . . . . . . . . . . . . . . . . .33
Loudspeakers (original equipment) - removal and refitting . . . . . . .31
Radio aerial pre-amplifier (original equipment) - removal and
refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .32
Radio or radio/cassette player (original equipment) - removal and
refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30
Rear entertainment console - removal and refitting . . . . . . . . . . . . .34
Rear headphone relay - removal and refitting . . . . . . . . . . . . . . . . .35
Rear window wiper motor - removal and refitting . . . . . . . . . . . . . .24
Seat adjusting motors - removal and refitting . . . . . . . . . . . . . . . . .19
Seat heating elements - removal and refitting . . . . . . . . . . . . . . . . .13
Sliding roof motor - removal and refitting . . . . . . . . . . . . . . . . . . . .20
Speed control system components - removal and refitting . . . . . . .28
Speedometer sender unit - removal and refitting . . . . . . . . . . . . . . .21
Switches - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
Window operating motor - removal and refitting . . . . . . . . . . . . . . .18
Windscreen, rear window and headlight washer components -
removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25
Windscreen wiper motor and linkage - removal and refitting . . . . .23
Wiper arms and blades - removal and refitting . . . . . . . . . . . . . . . .22
General
System type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 volt, negative earth
Light bulbs (typical)Fitting Wattage
Headlights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . H4 60/55
Auxiliary driving lights and front foglights . . . . . . . . . . . . . . . . . . . . . . . . H3 55
Side/parking lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Glass base 5
Direction indicators, reversing light and rear foglight . . . . . . . . . . . . . . . Bayonet 21
Stop and tail lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Bayonet 21/5
Door open/kerb illumination lights, luggage area light . . . . . . . . . . . . . . Bayonet 5
Number plate lights, reading light and footwell lights . . . . . . . . . . . . . . Glass base 5
Engine bay light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Bayonet 10
Interior lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Festoon 10
Vanity mirror light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Festoon 3
Glovebox light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Glass base 3
Ashtray light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Glass base 1.2
Instrument illumination, pilot and warning lights . . . . . . . . . . . . . . . . . . Glass base 1.2/2.5
Heater control light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Glass base 1
Automatic transmission selector light and clock light . . . . . . . . . . . . . . Bayonet 1.4
Fuses and circuit breakers- main fuse box
Fuse No Rating (A) Circuit(s) protected
1 20 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . LH main beam, LH auxiliary driving light
2 20 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . RH main beam, LH auxiliary driving light
3 10 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . LH dipped beam
4 10 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . RH dipped beam
5 10 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . LH side and tail lights
6 10 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . RH side and tail lights
13•1
Easy,suitable for
novice with little
experienceFairly easy,suitable
for beginner with
some experienceFairly difficult,
suitable for competent
DIY mechanicDifficult,suitable for
experienced DIY
mechanicVery difficult,
suitable for expert
DIY or professional
Degrees of difficulty
Specifications Contents
13
procarmanuals.com

13•2Body electrical system
Fuses and circuit breakers- main fuse box (continued)
Fuse NoRating (A)Circuit(s) protected
715 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Instrument illumination, number plate lights
810 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Control circuits for air conditioning, heated windscreen and ride
height control
930 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Headlight washer pump, tailgate and fuel filler flap release
1020 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Central locking system, interior lights, clock, mirror adjustment
1120 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Fuel pump (with air conditioning), taxi circuits
1210 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Hazard warning flasher
1330 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Heated seats, cigarette lighters
1430 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Horn
1530 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Wiper motors and screen washer pumps
1630 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Heated rear window, heated mirrors
1720 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Front foglights
1830 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Heater blower
1910 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Accessory circuits
2015 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Direction indicators, reversing lights
2115 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Stop-lights
2210 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Instrument and controls
23C20 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Power windows (front) and sliding roof
24C20 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Power windows (rear) and rear seat adjustment
C = Circuit breaker
Fuses and circuit breakers - auxiliary fuse box
Colour Rating (A)Circuit(s) protected
Black20 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Fuel-injection pump
Pink20 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Air conditioning cooling fan
Yellow20 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Anti-lock braking system control circuitry
Green30 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Anti-lock braking system pump
Brown30 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Heated windscreen (left-hand side)
Brown30 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Heated windscreen (right-hand side)
GreyC20 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Front seat adjustment
Orange20 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Ride height control
C = Circuit breaker
Relays in main fuse box
IdentificationFunction
I . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Ignition circuit
II . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Heated rear window and mirrors
III . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Power windows and sliding roof
IV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Seat belt warning
V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Intermittent wipe - front
VI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Intermittent wipe - rear
VII . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Headlight washer
VIII . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Interior light delay
IX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Rear seat adjustment
X . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Headlights (main beam)
XI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Engine auxiliary
XII . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Automatic transmission inhibitor
A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Spare
B . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Radio
C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Horn
D . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Tailgate release
E . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Spare
F . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Headlights (dipped beam)
G . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Seat heaters
H . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Front foglights
Other relays and modules
IdentificationFunction
Behind facia (centre):
L1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Lights on buzzer
L2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Rear fog light control
L3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Automatic transmission kickdown time
L4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Fuel pump (with air conditioning)
L5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Hydraulic switch
L6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Anti-theft alarm
Behind facia (passenger side):
M1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Manifold heater (carburettor) or fuel pump (fuel-injection)
M2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Power hold (carburettor) or inspection valve (fuel-injection)
M3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Heated windscreen (power)
procarmanuals.com

1For removal and refitting of the front
foglights, front direction indicators, direction
indicator repeaters and the number plate
lights, refer to the previous Section.
Headlight
2Unhook the direction indicator light unit
retaining spring. Withdraw the direction
indicator unit and allow it to hang.
3Pull out the rubber moulding from between
the base of the headlight and the bumper.
(This moulding may in fact be stuck to the
headlight surround.)
4Release the headlight surround retaininglugs, prising them carefully with a screwdriver.
Work from the outside towards the centre of
the vehicle. Remove the surround by pulling it
forwards and then sideways.
5Remove the radiator grille, secured by two
screws.
6Disconnect the headlight wiring connector.
Remove the two retaining screws, and the nut
on the side mounting (see illustrations). Draw
the headlight unit forwards and twist it to
remove it.
7Refit by reversing the removal operations.
Make sure that the locating pin on the outside
of the headlight unit engages in the hole in the
apron panel.
8If the new unit has been fitted, or if the
adjusting screws have been disturbed, have
the beam alignment checked without delay.9Note that the headlight lens can be renewed
independently of the rest of the unit, once the
securing clips have been removed (see
illustration).
Auxiliary driving light
10This is integral with the headlight unit.
Rear light cluster
Hatchback
11Remove the rear light cluster bulbholder
as described in the previous Section.
12Remove the six nuts which secure the rear
light unit (see illustration).
13Withdraw the light unit from the vehicle
and disconnect the multi-plug and wiring
harness from it (see illustration).
14Fit a new gasket to the light unit if the old
one was damaged.
15Refit by reversing the removal operations.
Saloon
16Remove the relevant trim panel from the
rear corner of the boot, noting that it may be
necessary to remove one or more of the rear
lower trim panel retaining screws (see
illustration).
17Disconnect the wiring connector from the
rear light cluster, then undo the four retaining
nuts and withdraw the light unit from the car
along with the rubber sealing gasket (see
illustration).
18Refitting is a reverse of removal ensuring
that the light unit rubber sealing gasket is in
good condition.
4Exterior light units - removal
and refitting
13•6Body electrical system
4.6a Headlight top mounting screw
4.13 Disconnecting the multi-plug from the
rear light unit
4.9 Removing a headlight lens securing clip4.12 Four rear light unit securing nuts
(arrowed) - there are two more out of sight
4.16 Remove the trim panel for access to
the rear light cluster retaining nuts4.17 Rear light cluster wiring connector (A)
and retaining nuts (B)
4.6b Headlight bottom mounting screw4.6c Headlight side mounting nut
procarmanuals.com

Estate
19This procedure is the same as described
above for the Saloon models noting that it is
necessary to remove the luggage
compartment side trim panel to gain access to
the light cluster retaining nuts.
1It is recommended that beam adjustment be
carried out by a Ford garage using optical
alignment equipment. In an emergency,
however, the following procedure will produce
acceptable results.
2The vehicle should be normally laden and the
tyre pressures must be correct. Park the vehicle
on level ground, approximately 10 metres (33
feet) in front of a flat wall or garage door.
3Draw a vertical line on the wall or door
corresponding to the centre-line of the vehicle.
(The position of this line can be determined by
marking the centres of the windscreen and
rear window with crayon, then viewing the wall
or door from the rear of the vehicle.)
4With the centre-line established, construct
the other lines shown (see illustration).
5Switch the headlights on to dipped beam.
Cover one headlight with cloth and adjust the
other, using the two screws at the rear of the
unit, to bring the centre of the beam to the
point C on the appropriate side of the
alignment chart (see illustration).6Transfer the cloth to theadjusted headlight,
and repeat the adjustment on the other headlight.
7Have the alignment checked professionally
at the first opportunity.
1Always switch the light off, or disconnect the
battery negative lead, before changing a bulb.
Courtesy light
2Carefully prise the light unit from its
location. If reading (spot) lights are fitted, prise
from the middle; if not, prise from one end
(seeillustration).
3Renew the bulb(s), detaching the reflector or
contact plate as necessary.
4Reassemble the light unit and press it home.
Vanity mirror light
5Carefully prise the frame off the mirror to
expose the bulbs(see illustration).
6Unclip the blown bulb(s) and press in the
new ones. Make sure that the spring contacts
which secure the bulb are clean and tight;
bend them slightly to improve their tension if
necessary.
7Check for correct operation, then snap the
mirror frame home.
Door lights
8The door open warning light can be
removed from the edge of the door by prisingthe lens from the inside edge (see
illustration).
9Renew the bulb and press the lens home.
10The kerb illumination light is renewed in a
similar way. Prise out the lens using the slot
provided, renew the bulb and refit the lens
(seeillustration).
6Interior lights - bulb renewal
5Headlight beam alignment
Body electrical system 13•7
13
5.5 Headlight beam adjustment screws
(arrowed)
6.2 Courtesy light bulb renewal
Prise at points arrowed
6.8 “Door open” light bulb renewal6.5 Mirror light bulb renewal
Prise frame at point arrowed
5.4 Headlight beam alignment
chart
A Distance between headlamp
centres
B Light-dark boundary
C Beam centre dipped
D Dipped beam pattern
H Height from ground to centre of
headlamps
X = 120 mm (4.7 in)
6.10 Kerb illumination light bulb renewal
procarmanuals.com

REF•12Glossary of Technical Terms
A
ABS (Anti-lock brake system)A system,
usually electronically controlled, that senses
incipient wheel lockup during braking and
relieves hydraulic pressure at wheels that are
about to skid.
Air bag An inflatable bag hidden in the
steering wheel (driver’s side) or the dash or
glovebox (passenger side). In a head-on
collision, the bags inflate, preventing the
driver and front passenger from being thrown
forward into the steering wheel or windscreen.
Air cleanerA metal or plastic housing,
containing a filter element, which removes
dust and dirt from the air being drawn into the
engine.
Air filter elementThe actual filter in an air
cleaner system, usually manufactured from
pleated paper and requiring renewal at regular
intervals.
Allen keyA hexagonal wrench which fits into
a recessed hexagonal hole.
Alligator clipA long-nosed spring-loaded
metal clip with meshing teeth. Used to make
temporary electrical connections.
AlternatorA component in the electrical
system which converts mechanical energy
from a drivebelt into electrical energy to
charge the battery and to operate the starting
system, ignition system and electrical
accessories.
Ampere (amp)A unit of measurement for the
flow of electric current. One amp is the
amount of current produced by one volt
acting through a resistance of one ohm.
Anaerobic sealerA substance used to
prevent bolts and screws from loosening.
Anaerobic means that it does not require
oxygen for activation. The Loctite brand is
widely used.
AntifreezeA substance (usually ethylene
glycol) mixed with water, and added to a
vehicle’s cooling system, to prevent freezing
of the coolant in winter. Antifreeze also
contains chemicals to inhibit corrosion and
the formation of rust and other deposits that
would tend to clog the radiator and coolant
passages and reduce cooling efficiency.
Anti-seize compoundA coating that
reduces the risk of seizing on fasteners that
are subjected to high temperatures, such as
exhaust manifold bolts and nuts.
AsbestosA natural fibrous mineral with great
heat resistance, commonly used in the
composition of brake friction materials.Asbestos is a health hazard and the dust
created by brake systems should never be
inhaled or ingested.
AxleA shaft on which a wheel revolves, or
which revolves with a wheel. Also, a solid
beam that connects the two wheels at one
end of the vehicle. An axle which also
transmits power to the wheels is known as a
live axle.
AxleshaftA single rotating shaft, on either
side of the differential, which delivers power
from the final drive assembly to the drive
wheels. Also called a driveshaft or a halfshaft.
BBall bearingAn anti-friction bearing
consisting of a hardened inner and outer race
with hardened steel balls between two races.
BearingThe curved surface on a shaft or in a
bore, or the part assembled into either, that
permits relative motion between them with
minimum wear and friction.
Big-end bearingThe bearing in the end of
the connecting rod that’s attached to the
crankshaft.
Bleed nippleA valve on a brake wheel
cylinder, caliper or other hydraulic component
that is opened to purge the hydraulic system
of air. Also called a bleed screw.
Brake bleedingProcedure for removing air
from lines of a hydraulic brake system.
Brake discThe component of a disc brake
that rotates with the wheels.Brake drumThe component of a drum brake
that rotates with the wheels.
Brake liningsThe friction material which
contacts the brake disc or drum to retard the
vehicle’s speed. The linings are bonded or
riveted to the brake pads or shoes.
Brake padsThe replaceable friction pads
that pinch the brake disc when the brakes are
applied. Brake pads consist of a friction
material bonded or riveted to a rigid backing
plate.
Brake shoeThe crescent-shaped carrier to
which the brake linings are mounted and
which forces the lining against the rotating
drum during braking.
Braking systemsFor more information on
braking systems, consult the Haynes
Automotive Brake Manual.
Breaker barA long socket wrench handle
providing greater leverage.
BulkheadThe insulated partition between
the engine and the passenger compartment.
CCaliperThe non-rotating part of a disc-brake
assembly that straddles the disc and carries
the brake pads. The caliper also contains the
hydraulic components that cause the pads to
pinch the disc when the brakes are applied. A
caliper is also a measuring tool that can be set
to measure inside or outside dimensions of an
object.
CamshaftA rotating shaft on which a series
of cam lobes operate the valve mechanisms.
The camshaft may be driven by gears, by
sprockets and chain or by sprockets and a
belt.
CanisterA container in an evaporative
emission control system; contains activated
charcoal granules to trap vapours from the
fuel system.
CarburettorA device which mixes fuel with
air in the proper proportions to provide a
desired power output from a spark ignition
internal combustion engine.
CastellatedResembling the parapets along
the top of a castle wall. For example, a
castellated balljoint stud nut.
CastorIn wheel alignment, the backward or
forward tilt of the steering axis. Castor is
positive when the steering axis is inclined
rearward at the top.
Canister
Brake bleeding
Bearing
Air filter
procarmanuals.com

REF•15Glossary of Technical Terms
RotorIn a distributor, the rotating device
inside the cap that connects the centre
electrode and the outer terminals as it turns,
distributing the high voltage from the coil
secondary winding to the proper spark plug.
Also, that part of an alternator which rotates
inside the stator. Also, the rotating assembly
of a turbocharger, including the compressor
wheel, shaft and turbine wheel.
RunoutThe amount of wobble (in-and-out
movement) of a gear or wheel as it’s rotated.
The amount a shaft rotates “out-of-true.” The
out-of-round condition of a rotating part.
SSealantA liquid or paste used to prevent
leakage at a joint. Sometimes used in
conjunction with a gasket.
Sealed beam lampAn older headlight design
which integrates the reflector, lens and
filaments into a hermetically-sealed one-piece
unit. When a filament burns out or the lens
cracks, the entire unit is simply replaced.
Serpentine drivebeltA single, long, wide
accessory drivebelt that’s used on some
newer vehicles to drive all the accessories,
instead of a series of smaller, shorter belts.
Serpentine drivebelts are usually tensioned by
an automatic tensioner.
ShimThin spacer, commonly used to adjust
the clearance or relative positions between
two parts. For example, shims inserted into or
under bucket tappets control valve
clearances. Clearance is adjusted by
changing the thickness of the shim.
Slide hammerA special puller that screws
into or hooks onto a component such as a
shaft or bearing; a heavy sliding handle on the
shaft bottoms against the end of the shaft to
knock the component free.SprocketA tooth or projection on the
periphery of a wheel, shaped to engage with a
chain or drivebelt. Commonly used to refer to
the sprocket wheel itself.
Starter inhibitor switchOn vehicles with an
automatic transmission, a switch that
prevents starting if the vehicle is not in Neutral
or Park.
StrutSee MacPherson strut.
TTappetA cylindrical component which
transmits motion from the cam to the valve
stem, either directly or via a pushrod and
rocker arm. Also called a cam follower.
ThermostatA heat-controlled valve that
regulates the flow of coolant between the
cylinder block and the radiator, so maintaining
optimum engine operating temperature. A
thermostat is also used in some air cleaners in
which the temperature is regulated.
Thrust bearingThe bearing in the clutch
assembly that is moved in to the release
levers by clutch pedal action to disengage the
clutch. Also referred to as a release bearing.
Timing beltA toothed belt which drives the
camshaft. Serious engine damage may result
if it breaks in service.
Timing chainA chain which drives the
camshaft.
Toe-inThe amount the front wheels are
closer together at the front than at the rear. On
rear wheel drive vehicles, a slight amount of
toe-in is usually specified to keep the front
wheels running parallel on the road by
offsetting other forces that tend to spread the
wheels apart.
Toe-outThe amount the front wheels are
closer together at the rear than at the front. On
front wheel drive vehicles, a slight amount of
toe-out is usually specified.
ToolsFor full information on choosing and
using tools, refer to the Haynes Automotive
Tools Manual.
TracerA stripe of a second colour applied to
a wire insulator to distinguish that wire from
another one with the same colour insulator.
Tune-upA process of accurate and careful
adjustments and parts replacement to obtain
the best possible engine performance.TurbochargerA centrifugal device, driven by
exhaust gases, that pressurises the intake air.
Normally used to increase the power output
from a given engine displacement, but can
also be used primarily to reduce exhaust
emissions (as on VW’s “Umwelt” Diesel
engine).
UUniversal joint or U-jointA double-pivoted
connection for transmitting power from a
driving to a driven shaft through an angle. A
U-joint consists of two Y-shaped yokes and a
cross-shaped member called the spider.
VValveA device through which the flow of
liquid, gas, vacuum, or loose material in bulk
may be started, stopped, or regulated by a
movable part that opens, shuts, or partially
obstructs one or more ports or passageways.
A valve is also the movable part of such a
device.
Valve clearanceThe clearance between the
valve tip (the end of the valve stem) and the
rocker arm or tappet. The valve clearance is
measured when the valve is closed.
Vernier caliperA precision measuring
instrument that measures inside and outside
dimensions. Not quite as accurate as a
micrometer, but more convenient.
ViscosityThe thickness of a liquid or its
resistance to flow.
VoltA unit for expressing electrical
“pressure” in a circuit. One volt that will
produce a current of one ampere through a
resistance of one ohm.
WWeldingVarious processes used to join metal
items by heating the areas to be joined to a
molten state and fusing them together. For
more information refer to the Haynes
Automotive Welding Manual.
Wiring diagramA drawing portraying the
components and wires in a vehicle’s electrical
system, using standardised symbols. For
more information refer to the Haynes
Automotive Electrical and Electronic Systems
Manual.
Serpentine drivebelt
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