Bulbs (continued) Wattage Type
Rear foglight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 382
Panel and warning lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2 987
Stop/tail lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21/5 380
Reversing lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 382
Interior light (early models) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 254
Interior light (later models) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 245
Glovebox light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 245
Footwell light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 239
Illuminated switches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.75 284
Windscreen wiper motor
Brush spring pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140 to 200 g
Minimum brush length . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.8 mm
Armature endfloat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.05 to 0.02 mm
Maximum pull to move rack in guide tubes . . . . . . . . . . . . . . . . . . . . . . 2.7 kg
1 General information and
precautions
General information
The electrical system is of 12-volt negative
earth type. Power for the lights and all
electrical accessories is supplied by a
lead/acid battery which is charged by the
dynamo or alternator.
This chapter covers repair and service
procedures for the various electrical
components and systems generally not
associated with the engine. Information on the
battery, ignition system, dynamo, alternator
and starter motor can be found in the relevant
Parts of Chapter 5.
Precautions
Warning: Before carrying out any
work on the electrical system,
read through the precautions
given in “Safety first!” at the
beginning of this manual and in Chapter 5.
Caution: Prior to working on any
component in the electrical system, the
battery negative lead should first be
disconnected, to prevent the possibility of
electrical short-circuits and/or fires. If a
radio/cassette player with anti-theft
security code is fitted, or if the vehicle is
equipped with anti-theft alarm system,
refer to the information given in the
reference sections of this manual before
disconnecting the battery.
2 Electrical fault finding -
general information
2
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, particularly where an electronic
control unit is used.
General
1 A 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 and
connectors 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 manual.
2 Before attempting to diagnose an electrical
fault, first study the appropriate wiring
diagram, to obtain a complete understanding
of the components included in the particular
circuit concerned. The possible sources of a
fault can be narrowed down by noting if 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.
3 Electrical 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.
4 The 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); an ohmmeter (to
measure resistance and check for continuity);
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.
5 To find the source of an intermittent wiring
fault (usually due to a poor or dirty
connection, or damaged wiring insulation), a
“wiggle” test can be performed on the wiring.
This involves wiggling 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.
6 Apart from problems due to poor
connections, two basic types of fault can
occur in an electrical circuit - open-circuit, or
short-circuit.
7 Open-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.
8 Short-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.
Finding an open-circuit
9 To check for an open-circuit, connect one
lead of a circuit tester or the negative lead of a
voltmeter either to the battery negative
terminal or to a known good earth.
10 Connect the other lead to a connector in
the circuit being tested, preferably nearest to
the battery or fuse. At this point, battery
voltage should be present, unless the lead
from the battery or the fuse itself is faulty
(bearing in mind that some circuits are live
only when the ignition switch is moved to a
particular position).
11 Switch on the circuit, then connect the
tester lead to the connector nearest the circuit
switch on the component side.
12 If 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 switch is problem-free.
13 Continue to check the remainder of the
circuit in the same fashion.
14 When 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.
Body electrical system 12•3
12
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