1992 FORD SIERRA mirror

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

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

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

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