transmission FORD SIERRA 1993 2.G Body Electrical System Workshop Manual

System type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12 volt, negative earth
BulbsFittingsWattage
Halogen headlamps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .H460/55
Auxiliary driving lamps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .H355
Front foglamps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .H355
Side lamps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Glass base5
Direction indicator lamps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Bayonet21
Brake/tail lamps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Bayonet21/4
Reversing lamp(s) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Bayonet21
Rear foglamp(s) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Bayonet21
Rear number plate lamps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Glass base5
Luggage compartment lamp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Bayonet10
Underbonnet lamp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Bayonet10
Courtesy lamp(s) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Bayonet10
Map reading lamps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Glass base5
Vanity mirror illumination lamp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Festoon3
Glove compartment lamp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Glass base3
Ashtray lamp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Glass base1.2
Warning lamps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Glass base1.2 or 2.5
Instrument illumination lamps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Glass base1.2 or 2.5
Heater control illumination lamp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Glass base1
Automatic transmission gear selector lamp . . . . . . . . . . . . . . . . . . . . . .Bayonet1.2
Clock illumination lamp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Bayonet1.4
Cigarette lighter lamp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Glass base1.2
Torque wrench settingsNmlbf ft
Trip computer fuel flow sensor unit fuel pipe unions . . . . . . . . . . . . . . .14 to 1710 to 13
General information
The electrical system is of the 12 volt.
negative earth type. Electricity is generated by
an alternator, belt-driven from the crankshaft
pulley. A lead-acid storage 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.
Precautions
It is necessary to take extra care when
working on the electrical system to avoid
damage to semi-conductor devices (diodes
and transistors), and to avoid the risk of
personal injury. In addition to the precautions
given in the
“Safety first!” Section at the
beginning of this manual, take note of the
following points when working on the system.
Always remove rings, watches, etc before
working on the electrical system. Even withthe battery disconnected, capacitive
discharge could occur if a component live
terminal is earthed through a metal object.
This could cause a shock or nasty burn.
Do not reverse the battery connections.
Components such as the alternator or any
other having semi-conductor circuitry could
be irreparably damaged.
If the engine is being started using jump
leads and a slave battery, connect the
batteries positive to positive and negative to
negative. This also applies when connecting a
battery charger.
Never disconnect the battery terminals, or
alternator multi-plug connector, when the
engine is running.
The battery leads and alternator multi-plug
must be disconnected before carrying out any
electric welding on the car.
Never use an ohmmeter of the type
incorporating a hand cranked generator for
circuit or continuity testing.
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 andconnectors 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.
2Electrical fault-finding - general
information
1General information and
precautions
13•2Body electrical system
Specifications

5To find the source of an intermittent wiring
fault (usually due to a poor or dirty
connection, or damaged wiring insulation), an
integrity test can 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
the circuit between the relevant connector
and the battery is problem-free.
13Continue to check the remainder of the
circuit in the same fashion.
14When 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
15To 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).
16Remove the relevant fuse from the circuit,
and connect a circuit tester or voltmeter to the
fuse connections.17Switch on the circuit, bearing in mind that
some circuits are live only when the ignition
switch is moved to a particular position.
18If voltage is present (indicated either by
the tester bulb lighting or a voltmeter reading,
as applicable), this means that there is a
short-circuit.
19If no voltage is present, but the fuse still
blows with the load(s) connected, this
indicates an internal fault in the load(s).
Finding an earth fault
20The battery negative terminal is connected
to “earth” - the metal of the
engine/transmission and the car body - and
most 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 fault. 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.
21To check whether a component is
properly earthed, disconnect the battery, 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.
22If an earth connection is thought to be
faulty, dismantle the connection, and clean
back to bare metal both the bodyshell and the
wire terminal, or the component’s earth
connection mating surface. 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 terminaland the bodyshell, to ensure a clean and
secure connection. When the connection is
remade, prevent the onset of corrosion in the
future by applying a coat of petroleum jelly or
silicone-based grease, or by spraying on (at
regular intervals) a proprietary ignition sealer.Location
1The main fuses and relays are located in a
box in the engine compartment on the right-
hand side of the bulkhead. The circuits
protected are identified by symbols on the
underside of the fusebox cover. On certain
models, additional relays and fuses are located
in various positions beneath the facia panels. If
uncertain of the location of an auxiliary relay or
fuse, it is suggested that a Ford dealer is
consulted, as the relay and fuse locations vary
substantially depending on model.
Renewal
2Always renew a fuse with one of identical
rating and never renew it more than once
without finding the source of the trouble
(usually a short circuit). Always switch off the
ignition before renewing a fuse or relay, and
when renewing the wiper motor fuse keep the
hands clear of the wiper linkage as it may
return to the parked position. Note that the
fuses are colour-coded as follows:
10ARed
15ABlue
20AYellow
25ANatural
10AGreen
3Access to the fuses and relays in the
fusebox is gained by removing the loose
cover and spring clip (if fitted), pulling the
plastic clip and removing the cover. All fuses
and relays are a push fit (see illustrations).
The fuse/relay plate can be released from the
fusebox for access to the wiring by carefully
levering the plastic lugs around the perimeter
of the plate.
4For details of direction indicator/hazard
warning flasher relay removal and refitting,
refer to the relevant Section of this Chapter.
3Fuses and relays - location and
renewal
Body electrical system 13•3
13
3.3b Fusebox cover removed to expose
fuses and relays (1.8 CVH model shown)3.3a Remove the loose cover for access to
the fusebox cover

Removal
1Disconnect the battery negative lead.
2For improved access, remove the securing
screws and unclip the lower and upper
steering column shrouds.
3Insert the ignition key and turn to position
“I”, then, working through the access hole,
depress the spring clip using a suitable tool
and pull the key to withdraw the lock barrel
and cylinder from the ignition switch housing.
The spring clip access hole is shown (see
illustration). Note that, on certain models, the
spring clip must be released by inserting the
tool through a small circular hole at the top of
the switch housing, above the rectangular slot
shown. Slight movement of the key may be
necessary to allow removal of the barrel and
cylinder.
4To remove the lock barrel from the cylinder
insert the key fully into the barrel and remove
the retaining circlip, taking care not to
damage the circlip location, then withdraw the
key approximately 5.0 mm (0.2 in) to retract
the lock barrel securing lug, and withdraw the
barrel from the cylinder.
5To remove the ignition switch, disconnect
the wiring plug, then remove the two grub
screws and withdraw the switch.
Refitting
6Refitting is a reversal of removal, bearing in
mind the following points.
7Note that the lock barrel can only be fitted
to the cylinder in one position, and check with
the key fully inserted that the barrel can be
turned from position “O” to “Ill” satisfactorily.
8The open jaws of the lock barrel retaining
circlip must align with the keyway register on
the cylinder, and the cylinder retaining circlip
must locate in the slot in the ignition switch
housing.
9On completion, check the operation of the
steering lock and ignition switch in all
positions.
1Disconnect the battery negative lead.
2Remove the securing screws and unclip the
lower and upper steering column shrouds.
3Remove the two securing screws and
disconnect the two wiring plugs, then
withdraw the switch from the steering column.
4Refitting is a reversal of removal.
1Disconnect the battery negative lead.2The relay is located on a bracket above the
steering column. Access is gained either by
removing the driver’s side lower facia panel or
the instrument panel.
3Unclip the relay from the bracket, and
disconnect the wiring plug (see illustration).
4Refitting is a reversal of removal. Check for
correct operation before refitting the facia
panel or instrument panel.
The procedure is identical to that described
for the direction indicator switch, except for
the additional removal and refitting of an earth
lead (see illustration).
1For automatic transmission models, refer to
Chapter 7, PartB. For manual gearbox
models, proceed as follows:
2Disconnect the battery negative lead.
3Apply the handbrake, jack up the front of
the vehicle and support on axle stands (see
“Jacking and Vehicle Support”).
4Working underneath the vehicle,
disconnect the wiring plug, then unscrew the
switch from the gearbox extension housing.
5Refitting is a reversal of removal, but make
sure that the wiring is routed clear of the
exhaust system.1Disconnect the battery negative lead.
Rocker switches and push button
switches
2Using a thin-bladed screwdriver, carefully
prise the switch from the facia panel.
3Disconnect the wiring plug and withdraw
the switch.
4Refitting is a reversal of removal.
Instrument panel illumination and
intermittent wipe rheostats
5Proceed as described in paragraphs 2 to 4.
Heater blower switch
6Carefully pull off the switch knob, using
pliers with padded jaws if necessary.
7Using a thin-bladed screwdriver, prise out
the switch front plate from the facia panel.
8Squeeze the switch retaining tabs, then
withdraw the switch and disconnect the wiring
plug (see illustration).
9Refitting is a reversal of removal.
Loudspeaker balance joystick
10Using a thin-bladed screwdriver, carefully
prise the joystick front plate from the facia
panel.
11Twist the joystick assembly retaining ring
anti-clockwise and remove the ring.
12Working behind the facia panel,
disconnect the wiring plug and slide out the
joystick assembly.
9Facia panel switches - removal
and refitting
8Reversing lamp switch -
renewal
7Lighting and wash/wipe
switch assembly - renewal
6Direction indicator/hazard
warning flasher relay - renewal
5Direction indicator and hazard
warning flasher switch
assembly - renewal
4Ignition switch and lock barrel
- removal and refitting
13•4Body electrical system
4.3 Ignition switch lock barrel spring clip
location (arrowed)
7.1 Lighting and wash/wipe switch
assembly earth lead securing screw
(arrowed)9.8 Heater blower switch removal. Switch
retaining tabs arrowed
6.3 Direction indicator/hazard warning
flasher relay location (arrowed)

dipstick from its tube and disconnect the
wiring plug.
31Refitting is a reversal of removal.
1Remove the instrument panel.
2Unclip the direction indicator relay from the
steering column support bracket (see
illustration).
3Unclip the “lights-on” warning module from
the steering column support bracket,
disconnect the wiring plug and remove the
module.
4Refitting is a reversal of removal.
1Disconnect the battery negative lead.
2To remove a lamp, simply prise it from its
location, using a thin-bladed screwdriver, and
disconnect the wiring (see illustrations).
When working on an overhead console-
mounted courtesy lamp, disconnect the
wiring between the map reading lamps and
the courtesy lamp before removing the
courtesy lamp.
3Refitting is a reversal of removal.1Disconnect the battery negative lead.
2Remove the courtesy lamp and disconnect
the map reading lamp wires.
3Push the map reading lamp out of its
location by inserting a finger through the
courtesy lamp aperture.
4Refitting is a reversal of removal.
1Disconnect the battery negative lead.
Courtesy lamp
2Remove the courtesy lamp.
3Unclip the bulb from the lamp. On models
fitted with an overhead console and map
reading lamps, the courtesy lamp reflector
must be unclipped for access to the bulb (see
illustration).
4Refitting is a reversal of removal.
Map reading lamp
5Remove the map reading lamp.
6Pull the bulbholder from the rear of the
lamp. The bulb is a push fit in the bulbholder
(see illustration).
7Refitting is a reversal of removal.
Glove compartment lamp
8Open the glove compartment and pull the
bulb from its holder.
9Refitting is a reversal of removal.
Ashtray lamp
10Open the ashtray and remove the tray
from its housing.
11Pull the bulbholder from the housing. The
bulb is a push fit in the bulbholder.
12Refitting is a reversal of removal.
Heater blower switch illumination
lamp
13Carefully pull off the switch knob, using
pliers with padded jaws if necessary. The bulb
is a bayonet fit in the end of the switch shaft.
14Refitting is a reversal of removal.
Heater control illumination lamp
15Refer to Chapter 12.
Vanity mirror illumination lamp
16Lower the sun visor and, using a thin-
bladed screwdriver, prise out the mirror and
diffuser assembly. Remove the festoon bulb(s)
from its/their spring contacts.
17Refitting is a reversal of removal.
Hazard flasher switch lamp
18Remove the securing screws and unclip
the upper steering column shroud.
19Ensure that the switch is in the “on”
position, then pull off the switch cap/bulb
cover. Carefully pull the bulb from the switch
using a pair of pliers with padded jaws.
20Refitting is a reversal of removal.
Automatic transmission gear
selector illumination lamp
21Unscrew the selector lever handle from
the threaded end of the lever, then remove the
three securing screws and withdraw the
centre console front upper panel.
22Pull of the selector gate cover to expose
the bulbholder. The bulb is a bayonet fit in the
bulbholder.
23Refitting is a reversal of removal.
Luggage compartment lamp
24Remove the lamp by carefully prising it
from its location using a thin-bladed
screwdriver. Unclip and remove the bulb (see
illustration).
25Refitting is a reversal of removal.
27Interior lamp bulbs - renewal
26Map reading lamp - removal
and refitting
25Courtesy lamp and luggage
compartment lamp - renewal
24“Lights-on” warning module
- renewal
13•10Body electrical system
24.2 “Lights-on” warning module location
A “Lights-on” warning module
B Direction indicator relay
C “Lights-on” warning module wiring plug
25.2b Removing a luggage compartment
lamp
27.6 Removing a map reading lamp bulb27.3 Overhead console-mounted courtesy
lamp bulb (arrowed)
25.2a Removing a courtesy lamp

Clock illumination lamp
26Remove the clock.
27The bulb is a bayonet fit in the rear of the
clock.
28Refitting is a reversal of removal.
1Disconnect the battery negative lead.
Removal and refitting
2Detach the wiring connector at the left-hand
bonnet hinge, and attach a length of string to
the end of the wire running from the lamp.
3If necessary, remove the underbonnet
insulation by prising out the two-piece plastic
securing clips, then working at the lamp, pull the
wiring and the string through the bonnet panel.
4Detach the string from the end of the wire,
and remove the screw securing the lamp to
the bonnet. Withdraw the lamp.
5Commence refitting by attaching the end of
the wiring to the string, and pulling the string
and wiring through the bonnet panel. Further
refitting is a reversal of removal.
Bulb renewal
6Simply press and twist the bulb to remove it
from the bulbholder (see illustration).
7Refitting is a reversal of removal.
Removal
1The horn(s) is/are located in front of the
radiator beneath the front panel (see
illustration). The horn(s) may be located on
either side of the vehicle depending on model.
2Disconnect the battery negative lead.
3Disconnect the wiring from the horn, then
unscrew the securing nut and washer and
withdraw the horn and bracket assembly
complete.
4Repeat the operations for the remaining
horn where applicable.
Refitting
5Refitting is a reversal of removal.
Removal
1On models fitted with a trip computer,
remove the speed sender unit.
2Remove the instrument panel.
3Pull the cable through the bulkhead into the
engine compartment, and where applicable
release it from the securing clips. On models
fitted with a trip computer, the upper section
of the cable can now be removed.
4Apply the handbrake, jack up the front of
the vehicle and support on axle stands (see
“Jacking and Vehicle Support”).
5On vehicles with a manual gearbox, extract
the circlip securing the cable end to the
extension housing and withdraw the cable
end (see illustration).
6On vehicles with automatic transmission,
remove the securing screw and disconnect
the cable end from the extension housing.
7The cable can now be withdrawn from the
vehicle, noting its routing so that it can be
refitted in the same position.
Refitting
8Refitting is a reversal of removal, but where
applicable, ensure that the speedometer
cable rubber sleeve is in place over the square
inner drive on the cable connector, and not in
the speedometer head. Position the cable so
that the coloured bands on the cable sheath
line up with the bulkhead grommet and the
clips in the engine compartment. Route the
cable as noted during removal.9On completion, pull the speedometer cable
from within the engine compartment to ensure
that the cable is straight between the
instrument panel and the bulkhead grommet.
1The wiper blades should be renewed when
they no longer clean the glass effectively.
2Lift the wiper arm away from the glass.
3With the blade at 90º to the arm, depress
the spring clip and slide the blade clear of the
hook, then slide the blade up off the arm.
4If necessary extract the two metal inserts
and unhook the wiper rubber.
5Fit the new rubber and blade in reverse
order, making sure where necessary that the
cut-outs in the metal inserts face each other.
Windscreen and rear wipers
1Lift the hinged covers and remove the nuts
and washers securing the arms to the spindles.
2Mark the arms and spindles in relation to each
other then prise off the arms using a screwdriver.
Take care not to damage the paintwork.
3Refitting is a reversal of removal.
Headlamp wipers
4The procedure is as described in
paragraphs 1 to 3, but the washer hose must
be disconnected from the nozzle on the wiper
arm (see illustration).
32Wiper arms - removal and
refitting
31Wiper blades - renewal
30Speedometer cable - removal
and refitting
29Horn - removal and refitting
28Underbonnet lamp - removal,
refitting and bulb renewal
Body electrical system 13•11
13
29.1 Horn location beneath front panel
30.5 Speedometer cable end fitting in
manual gearbox extension housing
28.6 Removing an underbonnet lamp bulb27.24 Removing a luggage compartment
lamp bulb
32.4 Removing a headlamp wiper arm