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

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

13Refitting is a reversal of removal, but note
that the wiring plug can only be fitted in one
position, and ensure that the joystick
assembly locating lug engages in the
corresponding hole in the facia panel.
1Disconnect the battery negative lead.
Models up to 1987
2Using a thin-bladed screwdriver, carefully
prise the switch from the door trim panel.
3Disconnect the wiring plug and withdraw
the switch (see illustration).
4Refitting is a reversal of removal.
Models from 1987
5Prise the securing screw cover from themirror control panel, then remove the screw
and withdraw the control panel.
6Depress the switch retaining tang, then
withdraw the switch from the control panel
and disconnect the wiring plug.
7Refitting is a reversal of removal.
1Disconnect the battery negative lead.
Switch
Models up to 1987
2Pull the trim insert from the centre of the
steering wheel, and disconnect the lead from
the horn push.
3Disconnect the two leads from the horn slip
ring, then remove the two securing screws
and withdraw the switch assembly (see
illustration).
4Refitting is a reversal of removal, but check
the operation of the switch on completion.
Models from 1987
5Using a thin-bladed screwdriver, carefully
prise the trim insert from the centre of the
steering wheel. Disconnect the wire.
6Prise the steering wheel centre disc from
the steering wheel, and disconnect the wire
(see illustration).
7Refitting is a reversal of removal.
Slip ring
8Remove the steering wheel.
9On models up to 1987, remove the switch
as described in paragraph 3.
10Release the three slip ring retaining tangs
and withdraw the slip ring from the steering
wheel.
11Refitting is a reversal of removal.
Slip ring contact finger
12Remove the steering wheel.
13Remove the securing screws and unclip
the lower and upper steering column shrouds.
14Disconnect the contact finger wiring plug,
and pull the contact finger housing from its
mounting (see illustration).
15Refitting is a reversal of removal.1Disconnect the battery negative lead.
2Open the door and remove the switch
securing screw.
3Withdraw the switch from the door pillar
and pull the wiring out sufficiently to prevent it
from springing back into the pillar (see
illustration).
4Disconnect the wiring and remove the
switch.
5Refitting is a reversal of removal.
1Disconnect the battery negative lead.
Models up to 1987
2A level-sensitive switch is fitted to the
tailgate.
3Unclip the tailgate trim panel.
4Disconnect the wiring from the switch
terminal, then remove the securing screw and
withdraw the switch, noting its fitted position
(see illustration).
5Refitting is a reversal of removal, but ensure
that the switch is refitted in its original
position, as noted during removal, and test
the operation of the switch on completion.
Models from 1987
6Where applicable, unclip the tailgate/boot
trim panel.
13Luggage compartment lamp
switch - removal and refitting
12Courtesy lamp switch -
renewal
11Horn switch assembly -
removal and refitting
10Electric door mirror switch -
removal and refitting
Body electrical system 13•5
13
11.6 Prise the trim insert from the steering
wheel, followed by the centre disc -
models from 1987
13.4 Luggage compartment lamp switch
location - models up to 198712.3 Withdrawing a courtesy lamp switch11.14 Horn switch slip ring contact finger
removal
11.3 Horn switch removal - models up to
1987. Switch securing screws arrowed10.3 Disconnect the wiring plug from the
door mirror switch - models up to 1987

Models up to 1992
1Disconnect the battery negative lead.
2Remove the securing screws and unclip the
lower and upper steering column shrouds.
3Where applicable, remove the instrument
panel illumination and intermittent wiper
rheostats.
4Unclip the cover for access to the lower
right-hand instrument panel surround
securing screw (see illustrations).
5Remove the two upper and two lower
securing screws, and withdraw the instrument
panel surround (see illustration).
6On models fitted with a trip computer,
unscrew the knurled nut and disconnect thespeedometer cable from the speed sender
unit on the engine compartment bulkhead.
7Detach the speedometer cable grommet
from the engine compartment bulkhead.
8Remove the two upper and two lower
securing screws, and withdraw the instrument
panel sufficiently to disconnect the
speedometer cable and the wiring plugs. The
speedometer cable can be released by
pushing the ribbed surface towards the centre
of the cable to free the catch. Remove the
instrument panel (see illustration).
9Refitting 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.
10On 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.
Models from 1992
11The procedure is as described above but
note that both instrument panel surround
lower securing screws are located beneath
plastic covers (see illustration).
12The steering column shrouds are secured
by six screws - five through the lower shroud,
and one through the upper shroud.
1Remove the instrument panel.
Panel illumination and warning
lamp bulbs
2Twist the relevant bulbholder anti-
clockwise and withdraw it from the printed
circuit board on the rear of the instrument
panel.
3The bulbs may be either a push-fit in the
bulbholder, or integral with the bulbholder in
which case the bulb and bulbholder must be
renewed as a unit (see illustrations).
4Refitting is a reversal of removal.
Panel lens
5Remove the three upper and three lower
securing screws and withdraw the lens from
the instrument panel.
6Refitting is a reversal of removal, but ensure
that the two locating pegs on the upper
corners of the instrument panel protrude
through the lens, and locate the lugs on the
lower edge of the lens in the cut-outs in the
instrument panel.
Printed circuit board
7Using a thin-bladed screwdriver, unclip and
remove the wiring plug socket.
8Remove all the illumination and warning
lamp bulbs as described earlier in this
Section.
9Remove all the nuts and washers from the
printed circuit board terminals.
10Unclip the printed circuit board from the
retainers at the back of the instrument panel,
and carefully withdraw the board over the
terminal pins on the gauges.
11Refitting is a reversal of removal.
21Instrument panel components
- removal and refitting
20Instrument panel - removal
and refitting
Body electrical system 13•7
13
20.5 Removing an upper instrument panel
surround securing screw
21.3b Removing an instrument panel
illumination bulb - bulb is integral with
bulbholder21.3a Removing an instrument panel
warning lamp bulb - bulb is a push-fit in
the bulbholder20.11 Removing an instrument panel
surround lower securing screw (cover
removed)
20.8 Withdraw the instrument panel and
disconnect the wiring plugs
20.4b . . . for access to the lower right-
hand instrument panel surround securing
screw20.4a Unclip the cover . . .

10Remove the headlamp securing bolt and
the two nuts, then release the anchor spring
and withdraw the direction indicator !amp unit
(see illustrations).
11Pull the headlamp forwards, then swivel it
and remove it sideways.
12If required, the headlamp lens can be
removed by releasing the spring clips around
its edge.
13Refitting is a reversal of removal.
14On completion, check the headlamp
alignment.
1It is recommended that the headlamp
alignment is carried out by a Ford dealer using
specialist beam setting equipment. However,
in an emergency the following procedure will
provide an acceptable light pattern.
2With the vehicle unladen, with a full tank of
fuel, and with the tyres correctly inflated,
position the vehicle approximately 10 metres(33 feet) in front of, and at right-angles to, a
wall or garage door.
3Draw a vertical line on the wall
corresponding to the centre line of the car.
The position of the line can be ascertained by
marking the centre of the front and rear
screens with crayon then viewing the wall
from the rear of the car.
4Complete the lines shown (see
illustration).
5Switch the headlamps on dipped beam and
adjust them as necessary using the knobs
located behind the headlamps (see
illustration). Cover the headlamp not being
checked with cloth.
1Disconnect the battery negative lead.
Saloon and Hatchback models
2Working inside the luggage compartment,
press the plastic retaining tab and remove thebulbholder assembly.
3Disconnect the wiring plug from the
bulbholder.
4Unscrew the securing nuts, and withdraw
the rear lamp unit from outside the vehicle.
Recover the gasket.
5Refitting is a reversal of removal.
Estate models
6Working inside the luggage compartment,
turn the retaining tabs a quarter-turn and
remove the rear side trim panel cover.
7Push out the retaining tabs and withdraw
the bulbholder.
8Disconnect the wiring plug from the
bulbholder.
9Unscrew the four securing nuts, and
withdraw the rear lamp unit from outside the
vehicle. Recover the gasket.
10Refitting is a reversal of removal.
43Rear lamp unit - removal and
refitting
42Headlamps - alignment
13•14Body electrical system
41.8 Disconnect the headlamp wiring plug
- models from 198741.10b . . . the upper securing nut . . .
42.5 Adjusting the headlamp alignment
42.4 Headlamp alignment chart
A Distance between headlamp centres
B Light/dark boundary
C Centre of dipped beam
D Dipped beam patternH Height of headlamp centre from ground
X = 160.0 mm (6.3 in) for all models up to 1987
120.0 mm (4.7 in) for all models from 1987
41.10c . . . and the side securing nut -
models from 1987
41.10a Remove the headlamp rear
securing bolt . . .

P100 models
11Remove the two securing screws and
detach the rear lamp wiring cover from the
side of the cargo area(see illustration).
12Working through the cargo area aperture,
unscrew the two wing nuts and remove the
rear lamp cover.
13Disconnect the wiring plug from the back
of the lamp unit.
14Unscrew the four securing nuts and
withdraw the lamp unit from outside the cargo
area. Recover the gasket.
15Refitting is a reversal of removal, but
ensure that the plastic washer between the
wiring plug and the lamp unit is seated
correctly, and make sure that the wiring
protective sheath is seated correctly in the
opening in the lamp cover.
1Disconnect the battery negative lead.
Models up to 1987
Low specification
2Push the lamp unit rearwards into the
bumper until the plastic retaining tang is heard
to click in the locked position.
3Withdraw the lamp unit from the front of the
bumper and disconnect the wiring plug (see
illustration).
4Commence refitting by reconnecting the
wiring plug.
5Release the retaining tang, then refit the
lamp unit to the bumper, ensuring that the
pivot on the lamp unit engages with the slot in
the bumper. Reconnect the battery.
High specification
6Press the release lever at the top of the
lamp unit upwards, and withdraw the unit
from the bumper. Disconnect the wiring plug.
7To refit, reconnect the wiring plug, then
push the lamp unit into the bumper until it
locates securely. Reconnect the battery.
All models from 1987
8Working in the engine compartment,
unhook the lamp unit anchor spring from itsanchorage next to the headlamp, then
withdraw the lamp unit sideways from its
recess (see illustrations). Disconnect the
bulbholder by twisting it anti-clockwise.
9Refitting is a reversal of removal, but ensure
that the locating pins on the lamp unit engage
with the corresponding holes in the headlamp
mounting panel.
1Disconnect the battery negative lead.
Models up to 1987
2To improve access, turn the steering onto
full lock.
3Remove the relevant wheel arch liner.
4Working under the wheel arch, depress the
retaining tabs and withdraw the lamp through
the outside of the wing (see illustration).
Disconnect the bulbholder by twisting it anti-
clockwise.
5Refitting is a reversal of removal.
Models from 1987
6To improve access, turn the steering onto
full lock.
7Working in the engine compartment,
disconnect the wiring plug.
8Remove the relevant wheel arch liner.
9Working under the wheel arch, twist the
lamp clockwise and withdraw it through theoutside of the wing. Feed the wiring through
the holes in the wing panels.
10Refitting is a reversal of removal.
1Disconnect the battery negative lead.
Models up to 1987
2Remove the relevant front direction
indicator lamp unit.
3Release the retaining catch on the inside
edge of the lamp, then withdraw the lamp
from the bumper and disconnect the wiring
plug (see illustration).
4Refitting is a reversal of removal.
46Front foglamps - removal and
refitting
45Front direction indicator side
repeater lamp - removal and
refitting
44Front direction indicator
lamp unit - removal and
refitting
Body electrical system 13•15
13
44.8a Unhook the front direction indicator
lamp unit anchor spring . . .
46.3 Front foglamp removal -
models up to 1987
A Retaining catch45.4 Withdrawing a front direction
indicator side repeater lamp -
models up to 1987
44.8b . . . and withdraw the lamp unit
44.3 Withdrawing a front direction
indicator lamp unit - “low specification”
models up to 198743.11 Rear lamp wiring cover (A) and rear
lamp cover (B) - P100 models