1985 FORD GRANADA air conditioning

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

The electrical system is a 12 volt, negative
earth type. Electricity is generated by an
alternator, belt-driven from the crankshaft pulley.
A lead-acid battery provides a reserve of power
for starting and when the demands of the system
temporarily exceed the alternator output.
The battery negative terminal is connected
to “earth” - vehicle metal - and most electrical
system components are wired so that they
only receive a positive feed, the current
returning via vehicle metal. This means that
the component mounting forms part of the
circuit. Loose or corroded mountings can
therefore cause apparent electrical faults.
Many semiconductor devices are used in
the electrical system, both in the “black
boxes” which control vehicle functions and in
other components. Semiconductors are very
sensitive to excessive (or wrong polarity)
voltage, and to extremes of heat. Observe the
appropriate precautions to avoid damage.
Although some repair procedures are given
in this Chapter, sometimes renewal of a well-
used item will prove more satisfactory. The
reader whose interests extend beyond
component renewal should obtain a copy of
the “Automobile Electrical Manual”, available
from the publishers of this book.
Before starting work on the electrical
system, read the precautions listed in “Safety
first!” at the beginning of the manual.
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
anti-lock braking systems), particularly where an
electronic control unit (ECU) is involved.
General
1A 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
Chapter.
2Before attempting to diagnose an electrical
fault, first study the appropriate wiring
diagram, to obtain a more complete
understanding of the components included in
the particular circuit concerned. The possible
sources of a fault can be narrowed down by
noting whether 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.
3Electrical 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. 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.
4The 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), a self-powered test
light (sometimes known as a continuity tester),
an ohmmeter (to measure resistance), 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.
5To find the source of an intermittent wiring
fault (usually due to a poor or dirty connection,
or damaged wiring insulation), an integrity testcan be performed on the wiring, which
involves moving 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.
6Apart from problems due to poor
connections, two basic types of fault can
occur in an electrical circuit - open-circuit or
short-circuit.
7Open-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, but will
not cause the relevant circuit fuse to blow.
8Short-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. Note: A short-
circuit that occurs in the wiring between a
circuit’s battery supply and its fuse will not
cause the fuse in that particular circuit to blow.
This part of the circuit is unprotected - bear
this in mind when fault-finding on the vehicle’s
electrical system.
Finding an open-circuit
9To check for an open-circuit, connect one
lead of a circuit tester or voltmeter to either the
negative battery terminal or a known good earth.
10Connect the other lead to a connector in
the circuit being tested, preferably nearest to
the battery or fuse.
11Switch on the circuit, bearing in mind that
some circuits are live only when the ignition
switch is moved to a particular position.
12If voltage is present (indicated either by
the tester bulb lighting or a voltmeter reading,
as applicable), this means that the section of
2Electrical fault-finding - general
information
1General information
Body electrical system 13•3
13
Other relays and modules (continued)
IdentificationFunction
Behind facia (passenger side) (continued):
M4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Heated windscreen (timer)
M5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Air conditioning cooling fan
M6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .ABS pump relay
M7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .ABS main relay
M8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .ABS control unit
M9 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Ride height control
Below instrument panel (driver’s side):
N1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Bulb failure warning unit
Below facia (passenger side):
P1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .ABS module
P2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Fuel-injection system module
Behind facia (passenger side):
R1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Speed control system module
R2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Auxiliary warning system module
R3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Rear audio console module
Torque wrench settingsNmlbf ft
Alternator adjusting strap:
To steering pump bracket (SOHC) . . . . . . . . . . . . . . . . . . . . . . . . . . .21 to 2616 to 19
To front cover (V6) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41 to 5130 to 38
procarmanuals.com

13•14Body electrical system
16.9 Typical arrangement of relays, control units and module
LHD shown - RHD is mirror image
A Taxi equipment
B Bulb failure module
C EEC IV module
D ABS module
E Rear headphone relay
F Auxiliary warning system control unit
G Speed control system module
H Anti-theft alarm module
I Warning display lighting
K Relay bank
1 Inlet manifold heater relay (carburettor)
2 Fuel pump relay (fuel-injection)
3 Power hold relay (carburettor)
4 Injector relay (fuel-injection)
5 Heated windscreen relay
6 Heated windscreen timer
7 Cooling fan relay (air conditioning)
8 ABS pump relay
9 ABS relay
10 ABS diodes
12 Ride height control relay
12 Day running lights relay (not UK)
procarmanuals.com

Introduction
A selection of good tools is a fundamental
requirement for anyone contemplating the
maintenance and repair of a motor vehicle. For
the owner who does not possess any, their
purchase will prove a considerable expense,
offsetting some of the savings made by doing-
it-yourself. However, provided that the tools
purchased meet the relevant national safety
standards and are of good quality, they will
last for many years and prove an extremely
worthwhile investment.
To help the average owner to decide which
tools are needed to carry out the various tasks
detailed in this manual, we have compiled
three lists of tools under the following
headings:
Maintenance and minor repair,
Repair and overhaul, and Special. Newcomers
to practical mechanics should start off with the
Maintenance and minor repairtool kit, and
confine themselves to the simpler jobs around
the vehicle. Then, as confidence and
experience grow, more difficult tasks can be
undertaken, with extra tools being purchased
as, and when, they are needed. In this way, a
Maintenance and minor repairtool kit can be
built up into a Repair and overhaultool kit over
a considerable period of time, without any
major cash outlays. The experienced do-it-
yourselfer will have a tool kit good enough for
most repair and overhaul procedures, and will
add tools from the Specialcategory when it is
felt that the expense is justified by the amount
of use to which these tools will be put.
Maintenance and minor repair tool
kit
The tools given in this list should be
considered as a minimum requirement if
routine maintenance, servicing and minor
repair operations are to be undertaken. We
recommend the purchase of combination
spanners (ring one end, open-ended the
other); although more expensive than open-
ended ones, they do give the advantages of
both types of spanner.
MCombination spanners:
Metric - 8, 9, 10, 11, 12, 13, 14, 15, 17 &
19 mmMAdjustable spanner - 35 mm jaw (approx)
MGearbox and final drive filler/level plug keys
MSpark plug spanner (with rubber insert)
MSpark plug gap adjustment tool
MSet of feeler blades
MBrake bleed nipple spanner
MScrewdrivers:
Flat blade - approx 100 mm long x 6 mm dia
Cross blade - approx 100 mm long x 6 mm
dia
MCombination pliers
MHacksaw (junior)
MTyre pump
MTyre pressure gauge
MOil can
MOil filter removal tool
MFine emery cloth
MWire brush (small)
MFunnel (medium size)
Repair and overhaul tool kit
These tools are virtually essential for anyone
undertaking any major repairs to a motor
vehicle, and are additional to those given in the
Maintenance and minor repairlist. Included in
this list is a comprehensive set of sockets.
Although these are expensive, they will be
found invaluable as they are so versatile -
particularly if various drives are included in the
set. We recommend the half-inch square-drive
type, as this can be used with most proprietary
torque wrenches. If you cannot afford a socket
set, even bought piecemeal, then inexpensive
tubular box spanners are a useful alternative.
The tools in this list will occasionally need to
be supplemented by tools from the Special
list:
MSockets (or box spanners) to cover range in
previous list (including Torx sockets)*
MReversible ratchet drive (for use with
sockets) (see illustration)
MExtension piece, 250 mm (for use with
sockets)
MUniversal joint (for use with sockets)
MTorque wrench (for use with sockets)
MSelf-locking grips
MBall pein hammerMSoft-faced mallet (plastic/aluminium or
rubber)
MScrewdrivers:
Flat blade - long & sturdy, short (chubby),
and narrow (electrician’s) types
Cross blade - Long & sturdy, and short
(chubby) types
MPliers:
Long-nosed
Side cutters (electrician’s)
Circlip (internal and external)
MCold chisel - 25 mm
MScriber
MScraper
MCentre-punch
MPin punch
MHacksaw
MBrake hose clamp
MBrake/clutch bleeding kit
MSelection of twist drills
MSteel rule/straight-edge
MAllen keys (inc. splined/Torx type) (see
illustration)
MSelection of files
MWire brush
MAxle stands
MJack (strong trolley or hydraulic type)
MLight with extension lead
* Some Imperial sized nuts and bolts may be
found on air conditioning and automatic
transmission components
Special tools
The tools in this list are those which are not
used regularly, are expensive to buy, or which
need to be used in accordance with their
manufacturer’s instructions. Unless relatively
difficult mechanical jobs are undertaken
frequently, it will not be economic to buy many
of these tools. Where this is the case, you
could consider clubbing together with friends
(or joining a motorists’ club) to make a joint
purchase, or borrowing the tools against a
deposit from a local garage or tool hire
specialist. It is worth noting that many of the
larger DIY superstores now carry a large range
of special tools for hire at modest rates.
REF•1
Spline bit setValve spring compressorSockets and reversible ratchet drive
Tools and Working Facilities
procarmanuals.com

REF•13Glossary of Technical Terms
Catalytic converterA silencer-like device in
the exhaust system which converts certain
pollutants in the exhaust gases into less
harmful substances.
CirclipA ring-shaped clip used to prevent
endwise movement of cylindrical parts and
shafts. An internal circlip is installed in a
groove in a housing; an external circlip fits into
a groove on the outside of a cylindrical piece
such as a shaft.
ClearanceThe amount of space between
two parts. For example, between a piston and
a cylinder, between a bearing and a journal,
etc.
Coil springA spiral of elastic steel found in
various sizes throughout a vehicle, for
example as a springing medium in the
suspension and in the valve train.
CompressionReduction in volume, and
increase in pressure and temperature, of a
gas, caused by squeezing it into a smaller
space.
Compression ratioThe relationship between
cylinder volume when the piston is at top
dead centre and cylinder volume when the
piston is at bottom dead centre.
Constant velocity (CV) jointA type of
universal joint that cancels out vibrations
caused by driving power being transmitted
through an angle.
Core plugA disc or cup-shaped metal device
inserted in a hole in a casting through which
core was removed when the casting was
formed. Also known as a freeze plug or
expansion plug.
CrankcaseThe lower part of the engine
block in which the crankshaft rotates.
CrankshaftThe main rotating member, or
shaft, running the length of the crankcase,
with offset “throws” to which the connecting
rods are attached.
Crocodile clipSee Alligator clipDDiagnostic codeCode numbers obtained by
accessing the diagnostic mode of an engine
management computer. This code can be
used to determine the area in the system
where a malfunction may be located.
Disc brakeA brake design incorporating a
rotating disc onto which brake pads are
squeezed. The resulting friction converts the
energy of a moving vehicle into heat.
Double-overhead cam (DOHC)An engine
that uses two overhead camshafts, usually
one for the intake valves and one for the
exhaust valves.
Drivebelt(s)The belt(s) used to drive
accessories such as the alternator, water
pump, power steering pump, air conditioning
compressor, etc. off the crankshaft pulley.
DriveshaftAny shaft used to transmit
motion. Commonly used when referring to the
axleshafts on a front wheel drive vehicle.
Drum brakeA type of brake using a drum-
shaped metal cylinder attached to the inner
surface of the wheel. When the brake pedal is
pressed, curved brake shoes with friction
linings press against the inside of the drum to
slow or stop the vehicle.
EEGR valveA valve used to introduce exhaust
gases into the intake air stream.
Electronic control unit (ECU)A computer
which controls (for instance) ignition and fuel
injection systems, or an anti-lock braking
system. For more information refer to the
Haynes Automotive Electrical and Electronic
Systems Manual.
Electronic Fuel Injection (EFI)A computer
controlled fuel system that distributes fuel
through an injector located in each intake port
of the engine.
Emergency brakeA braking system,
independent of the main hydraulic system,
that can be used to slow or stop the vehicle if
the primary brakes fail, or to hold the vehicle
stationary even though the brake pedal isn’t
depressed. It usually consists of a hand lever
that actuates either front or rear brakes
mechanically through a series of cables and
linkages. Also known as a handbrake or
parking brake.EndfloatThe amount of lengthwise
movement between two parts. As applied to a
crankshaft, the distance that the crankshaft
can move forward and back in the cylinder
block.
Engine management system (EMS)A
computer controlled system which manages
the fuel injection and the ignition systems in
an integrated fashion.
Exhaust manifoldA part with several
passages through which exhaust gases leave
the engine combustion chambers and enter
the exhaust pipe.
F
Fan clutchA viscous (fluid) drive coupling
device which permits variable engine fan
speeds in relation to engine speeds.
Feeler bladeA thin strip or blade of hardened
steel, ground to an exact thickness, used to
check or measure clearances between parts.
Firing orderThe order in which the engine
cylinders fire, or deliver their power strokes,
beginning with the number one cylinder.
Flywheel A heavy spinning wheel in which
energy is absorbed and stored by means of
momentum. On cars, the flywheel is attached
to the crankshaft to smooth out firing
impulses.
Free playThe amount of travel before any
action takes place. The “looseness” in a
linkage, or an assembly of parts, between the
initial application of force and actual
movement. For example, the distance the
brake pedal moves before the pistons in the
master cylinder are actuated.
FuseAn electrical device which protects a
circuit against accidental overload. The typical
fuse contains a soft piece of metal which is
calibrated to melt at a predetermined current
flow (expressed as amps) and break the
circuit.
Fusible linkA circuit protection device
consisting of a conductor surrounded by
heat-resistant insulation. The conductor is
smaller than the wire it protects, so it acts as
the weakest link in the circuit. Unlike a blown
fuse, a failed fusible link must frequently be
cut from the wire for replacement.Catalytic converter
Crankshaft assembly
Accessory drivebelts
Feeler blade
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REF•14Glossary of Technical Terms
GGapThe distance the spark must travel in
jumping from the centre electrode to the side
electrode in a spark plug. Also refers to the
spacing between the points in a contact
breaker assembly in a conventional points-
type ignition, or to the distance between the
reluctor or rotor and the pickup coil in an
electronic ignition.
GasketAny thin, soft material - usually cork,
cardboard, asbestos or soft metal - installed
between two metal surfaces to ensure a good
seal. For instance, the cylinder head gasket
seals the joint between the block and the
cylinder head.
GaugeAn instrument panel display used to
monitor engine conditions. A gauge with a
movable pointer on a dial or a fixed scale is an
analogue gauge. A gauge with a numerical
readout is called a digital gauge.
HHalfshaftA rotating shaft that transmits
power from the final drive unit to a drive
wheel, usually when referring to a live rear
axle.
Harmonic balancerA device designed to
reduce torsion or twisting vibration in the
crankshaft. May be incorporated in the
crankshaft pulley. Also known as a vibration
damper.
HoneAn abrasive tool for correcting small
irregularities or differences in diameter in an
engine cylinder, brake cylinder, etc.
Hydraulic tappetA tappet that utilises
hydraulic pressure from the engine’s
lubrication system to maintain zero clearance
(constant contact with both camshaft and
valve stem). Automatically adjusts to variation
in valve stem length. Hydraulic tappets also
reduce valve noise.
IIgnition timingThe moment at which the
spark plug fires, usually expressed in the
number of crankshaft degrees before the
piston reaches the top of its stroke.
Inlet manifoldA tube or housing with
passages through which flows the air-fuel
mixture (carburettor vehicles and vehicles with
throttle body injection) or air only (port fuel-
injected vehicles) to the port openings in the
cylinder head.
JJump startStarting the engine of a vehicle
with a discharged or weak battery by
attaching jump leads from the weak battery to
a charged or helper battery.
LLoad Sensing Proportioning Valve (LSPV)A
brake hydraulic system control valve that
works like a proportioning valve, but also
takes into consideration the amount of weight
carried by the rear axle.
LocknutA nut used to lock an adjustment
nut, or other threaded component, in place.
For example, a locknut is employed to keep
the adjusting nut on the rocker arm in
position.
LockwasherA form of washer designed to
prevent an attaching nut from working loose.
MMacPherson strutA type of front
suspension system devised by Earle
MacPherson at Ford of England. In its original
form, a simple lateral link with the anti-roll bar
creates the lower control arm. A long strut - an
integral coil spring and shock absorber - is
mounted between the body and the steering
knuckle. Many modern so-called MacPherson
strut systems use a conventional lower A-arm
and don’t rely on the anti-roll bar for location.
MultimeterAn electrical test instrument with
the capability to measure voltage, current and
resistance.
NNOxOxides of Nitrogen. A common toxic
pollutant emitted by petrol and diesel engines
at higher temperatures.
OOhmThe unit of electrical resistance. One
volt applied to a resistance of one ohm will
produce a current of one amp.
OhmmeterAn instrument for measuring
electrical resistance.
O-ringA type of sealing ring made of a
special rubber-like material; in use, the O-ring
is compressed into a groove to provide the
sealing action.
Overhead cam (ohc) engineAn engine with
the camshaft(s) located on top of the cylinder
head(s).Overhead valve (ohv) engineAn engine with
the valves located in the cylinder head, but
with the camshaft located in the engine block.
Oxygen sensorA device installed in the
engine exhaust manifold, which senses the
oxygen content in the exhaust and converts
this information into an electric current. Also
called a Lambda sensor.
PPhillips screwA type of screw head having a
cross instead of a slot for a corresponding
type of screwdriver.
PlastigageA thin strip of plastic thread,
available in different sizes, used for measuring
clearances. For example, a strip of Plastigage
is laid across a bearing journal. The parts are
assembled and dismantled; the width of the
crushed strip indicates the clearance between
journal and bearing.
Propeller shaftThe long hollow tube with
universal joints at both ends that carries
power from the transmission to the differential
on front-engined rear wheel drive vehicles.
Proportioning valveA hydraulic control
valve which limits the amount of pressure to
the rear brakes during panic stops to prevent
wheel lock-up.
RRack-and-pinion steeringA steering system
with a pinion gear on the end of the steering
shaft that mates with a rack (think of a geared
wheel opened up and laid flat). When the
steering wheel is turned, the pinion turns,
moving the rack to the left or right. This
movement is transmitted through the track
rods to the steering arms at the wheels.
RadiatorA liquid-to-air heat transfer device
designed to reduce the temperature of the
coolant in an internal combustion engine
cooling system.
RefrigerantAny substance used as a heat
transfer agent in an air-conditioning system.
R-12 has been the principle refrigerant for
many years; recently, however, manufacturers
have begun using R-134a, a non-CFC
substance that is considered less harmful to
the ozone in the upper atmosphere.
Rocker armA lever arm that rocks on a shaft
or pivots on a stud. In an overhead valve
engine, the rocker arm converts the upward
movement of the pushrod into a downward
movement to open a valve.
Adjusting spark plug gap
Plastigage
Gasket
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