heater FORD SIERRA 1985 1.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

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