horn FORD SIERRA 1985 1.G Body Electrical System Workshop Manual

Chapter 13
Body electrical system
Anti-theft alarm - location, removal and refitting . . . . . . . . . . . . . . . .51
Auxiliary warning system components - location, testing, removal and
refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
Brake lamp switch - renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
Central door locking components - operation, removal and refitting .50
Cigarette lighter - renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
Clock - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
Courtesy lamp and luggage compartment lamp - renewal . . . . . . . .25
Courtesy lamp switch - renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
Direction indicator and hazard warning flasher switch assembly -
renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
Direction indicator/hazard warning flasher relay - renewal . . . . . . . . .6
Electrical door mirror switch - removal and refitting . . . . . . . . . . . . .10
Electrical fault finding - general information . . . . . . . . . . . . . . . . . . . . .2
Electric sunroof components - removal and refitting . . . . . . . . . . . . .17
Electric window components - removal and refitting . . . . . . . . . . . . .49
Exterior lamp bulbs - renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .48
Facia panel switches - removal and refitting . . . . . . . . . . . . . . . . . . . .9
Front direction indicator lamp unit - removal and refitting . . . . . . . . .44
Front direction indicator side repeater lamp - removal and refitting . .45
Front foglamps - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . .46
Fuses and relays - location and renewal . . . . . . . . . . . . . . . . . . . . . . .3
General information and precautions . . . . . . . . . . . . . . . . . . . . . . . . .1
Handbrake “on” warning lamp switch - renewal . . . . . . . . . . . . . . . .14
Headlamps - alignment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .42
Headlamp unit - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . .41
Headlamp wiper motor - removal and refitting . . . . . . . . . . . . . . . . . .40
Horn - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29
Horn switch assembly - removal and refitting . . . . . . . . . . . . . . . . . .11
Ignition switch and lock barrel - removal and refitting . . . . . . . . . . . . .4
Instrument panel - removal and refitting . . . . . . . . . . . . . . . . . . . . . .20Instrument panel components - removal and refitting . . . . . . . . . . . .21
Integral heated rear window/radio aerial amplifier - removal and
refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .54
Interior lamp bulbs - renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27
Lighting and wash/wipe switch assembly - renewal. . . . . . . . . . . . . . .7
“Lights-on” warning module - renewal . . . . . . . . . . . . . . . . . . . . . . . .24
Loudspeakers - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . .55
Luggage compartment lamp switch - removal and refitting . . . . . . .13
Map reading lamp - removal and refitting . . . . . . . . . . . . . . . . . . . . .26
Oil pressure warning lamp switch - renewal . . . . . . . . . . . . . . . . . . . .16
Radio aerial (exterior-mounted) - removal and refitting . . . . . . . . . . .53
Radio/cassette player - removal and refitting . . . . . . . . . . . . . . . . . . .57
Radio/cassette player power amplifier - removal and refitting . . . . . .56
Rear lamp unit - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . .43
Rear number plate lamp - removal and refitting . . . . . . . . . . . . . . . . .47
Rear window washer fluid reservoir - removal and refitting . . . . . . . .39
Rear window washer pump - removal and refitting . . . . . . . . . . . . . .38
Rear window wiper motor - removal and refitting . . . . . . . . . . . . . . .37
Reversing lamp switch - renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
Seat heating pad - removal and refitting . . . . . . . . . . . . . . . . . . . . . .52
Speedometer cable - removal and refitting . . . . . . . . . . . . . . . . . . . .30
Trip computer components - removal and refitting . . . . . . . . . . . . . .22
Underbonnet lamp - removal, refitting and bulb renewal . . . . . . . . . .28
Washer nozzles - removal and refitting . . . . . . . . . . . . . . . . . . . . . . .33
Windscreen/headlamp washer fluid reservoir - removal and refitting . .36
Windscreen/headlamp washer pump - removal and refitting . . . . . .35
Windscreen wiper motor and linkage - removal and refitting . . . . . . .34
Wiper arms - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . .32
Wiper blades - renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31
Wiring diagrams - general information . . . . . . . . . . . . . . . . . . . . . . . .58
13•1
Contents
13Easy,suitable for
novice with little
experienceFairly easy,suitable
for beginner with
some experienceFairly difficult,
suitable for competent
DIY mechanic
Difficult,suitable for
experienced DIY
mechanicVery difficult,
suitable for expert
DIY or professional
Degrees of difficulty

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

Location
1The AWS control unit, and (when fitted) the
bulb failure monitor, are located behind the
glovebox on models up to 1987.
2On models from 1987, the control and bulb
failure modules are located behind the driver’s
side footwell trim panel.
Testing
3Thorough testing and fault finding should
be left to a Ford dealer or other electrical
specialist, having test equipment. Unskilled or
uninformed testing may cause damage.
4Investigation of malfunctions should begin
by checking that all wiring is intact and
securely connected. If checking wires or
sensors for continuity, always disconnect the
control unit and/or bulb failure monitor before
so doing, otherwise damage may be caused.
5Note that false oil level readings can result if
the car is parked on a slope. False bulb failure
warnings may occur if incorrect wattage bulbs
are fitted.
Removal and refitting
6Disconnect the battery negative lead.
Warning lamp bulbs
7Remove the single screw from the top edge
of the facia panel in which the warning lamps
are housed, then withdraw the facia panel
(see illustration).
8Twist the relevant bulbholder through 90º to
remove it from the rear of the facia panel. The
bulb is integral with the bulbholder and must
be renewed as a unit (see illustration).
9Refitting is a reversal of removal.
Graphic display unit and bulbs
10Remove the clock or trip computer.
11Remove the display unit retaining screw
and the retainer, then pull the unit forwards
and disconnect the wiring plug using a thin-
bladed screwdriver (see illustrations).
12To renew a bulb, remove the two securing
screws and pull the circuit board from the
back of the unit to reveal the bulbs. The bulbs
are a push-fit.
13Refitting is a reversal of removal.
Control unit and bulb failure monitor
14Unclip the trim panel from the lower edge
of the passenger side lower facia panel.
15On models up to 1987, pull off the two
clips to release the control unit/bulb failure
monitor mounting bracket. Depress the
retaining tab and disconnect the relevant
wiring plug, then remove the two securing
screws and withdraw the control unit/bulb
failure monitor (see illustration).
16On models from 1987, release the
retaining tang and carefully slide the control
unit/bulb failure monitor downwards. Depress
the retaining tab and disconnect the relevant
wiring plug, then withdraw the control
unit/bulb failure monitor.
17Refitting is a reversal of removal. Note
that when both a control unit and bulb failure
monitor are fitted, the control unit wiring plug
is coloured brown, and the bulb failure
monitor wiring plug is coloured green.
Ice warning sender
18This sender is located beneath the front
panel on the right-hand side of the vehicle.
19Where necessary, for improved access
remove the horn.
20Depress the two retaining tangs,
disconnect the wiring plug and withdraw the
sender unit from the slot in the front panel.
21Refitting is a reversal of removal.
Door/tailgate/boot lid ajar switches
22Remove the relevant lock.
23Pull the switch from its location in the lock
body, disconnect the wiring plug (if not
already done) and withdraw the switch (see
illustration).24Refitting is a reversal of removal.
Low coolant level sensor
25Refer to Chapter 3.
Low washer fluid level switch
26Syphon out the contents of the reservoir,
then prise the switch from its grommet using a
thin-bladed screwdriver. Disconnect the
wiring plug.
27Refitting is a reversal of removal, using a
new grommet if necessary. Use a little liquid
detergent as a lubricant.
28On completion, refill the reservoir.
Low fuel level switch
29The switch is integral with the fuel level
sender unit. Details of fuel level sender unit
removal and refitting are given in Chapter 4.
Low oil level switch
30The switch is integral with the oil level
dipstick. To remove, simply withdraw the
23Auxiliary warning system
components - location,
testing, removal and refitting
Body electrical system 13•9
13
23.11a Removing the graphic display unit
retaining screw
23.23 Door lock and door ajar switch23.15 Auxiliary warning system control unit
location
23.11b Disconnecting the wiring plug from
the graphic display unit
23.8 Removing an auxiliary warning lamp
bulb23.7 Remove the screw from the warning
lamp facia panel

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

21Remove the two securing screws, and
detach the motor from the lock assembly.
22Refitting is a reversal of removal, ensuring
that the motor operating rod engages with the
lock lever.
Note: The alarm system has a self-diagnosis
function, which allows a Ford dealer to carry
out fault diagnosis, using suitable specialist
equipment. In the event of a problem with the
alarm system, it is advisable not to tamper
with the components until appropriate fault
diagnosis has been carried out.Location
1From 1990, certain models are fitted with
an anti-theft alarm(see illustration).
2The alarm system consists of a control
module mounted behind the driver’s side
facia; trip switches fitted to the doors,
tailgate/boot lid, and bonnet; activating
switches fitted to the front door locks; an
additional horn mounted at the bulkhead next
to the battery and an indicator light mounted
on the top of the facia.
Module - removal and refitting
3Disconnect the battery negative lead.
4Release the carpet trim panel from under
the driver’s side facia. 5Reach up behind the facia and locate the
control module. Release the plastic retaining
clips using a screwdriver, and lower the
module.
6Disconnect the wiring plug and withdraw
the module.
7Refitting is a reversal of removal.
Removal
1Disconnect the battery negative lead.
2Remove the seat.
3Remove the seat cushion trim or backrest
trim as necessary.
4Note which way round the pad is fitted,
then remove the wire clips and adhesive tape
which secure it to the seat. Retrieve the tie-
rod and fit it to the new pad.
Refitting
5Fit the new pad with the thermostat facing
the cushion foam(see illustration).Secure
the pad with wire clips and tape, making sure
that it is not too tight - it must be able to flex
when sat on.
6Refit the cushion or backrest trim, as
applicable, being careful not to trap or kink
the pad.
7Refit the seat, reconnect the wiring and
check the pads for correct operation.
52Seat heating pad - removal
and refitting
51Anti-theft alarm - location,
removal and refitting
Body electrical system 13•19
13
50.19b Rear door central locking motor
securing screws (arrowed) -
models from 199050.19a Front door central locking motor
securing screws (arrowed) -
models from 1990
51.1 Anti-theft alarm
system components
A Tailgate/boot lid
switch
B Control module
C Horn
D Bonnet switch
E Door switch
F Activating switch