1990 FORD SIERRA fuel type

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