1987 BMW 5 SERIES Power steering

axle (it probably will), use a puller to remove
the race from the stub axle. If you can’t get
the race off with a puller, take the stub axle to
an engineering works and have it pressed off.
13Remove the large circlip that retains the
bearing in the bearing housing (see
illustration), then drive the bearing out of the
bearing housing with a large socket or a
suitable piece of pipe (see illustration).
14Refitting is basically a reversal of removal,
bearing in mind the following points:
a) Fit the new bearing using a large socket
or a suitable piece of pipe, with an
outside diameter the same diameter as
the outer race (see illustration). Don’t
apply force to the inner race. Make sure
the bearing is fully seated against the
back of the bore. Refit the circlip, making
sure it’s fully seated into its groove.
b) BMW dealers use special tools (Part Nos.
23 1 1300, 33 4 080 and 33 4 020) to pull
the stub axle into the bearing, because
the smooth portion between the splined
portion of the stub axle and the flange is a
press-fit, and knocks out the wheel
bearing inner race during refitting of the
stub axle. However, you can refit the stub
axle without these tools, using the old
inner race and a piece of pipe 13 mm
long by 38 mm inside diameter (seeillustration). First, insert the stub axle
through the new bearing until the
threaded portion protrudes from the inner
race. Refit the nut and tighten it until the
splined portion of the stub axle shaft
bottoms against the nut. You’ll need to
hold the stub axle flange with a lever or a
large screwdriver while tightening the nut
(see illustration). Remove the nut, refit
your piece of pipe, centred on the inner
race and refit the nut (see illustration).
Tighten the nut again until it bottoms
against the splines. Remove the nut, refit
the old inner race, refit the nut and tighten
it once more until it bottoms against the
splines. Remove the nut, remove the old
inner race, refit your piece of pipe, refit
the old inner race, refit the nut and tighten
it until it bottoms against the splines.
Remove the nut, the old race and the
pipe. Refit the drive flange, refit the nut
and tighten it securely, but don’t attempt
to tighten it to the final torque until the
vehicle is lowered to the ground.
c) Refit the wheel and lower the vehicle to
the ground before tightening the stub axle
nut to the torque listed in this Chapter’s
Specifications.
15The remainder of refitting is the reverse of
removal.
16 Steering system-
general information
On 3-Series models, the steering wheel and
steering column are connected to a rack-and-
pinion steering gear (power-assisted where
applicable) via a short universal joint shaft.
When the steering wheel is turned, the
steering column and universal joint turn a
pinion gear shaft on top of the rack. The
pinion gear teeth mesh with the gear teeth of
the rack, so the rack moves right or left in the
housing when the pinion is turned. The
movement of the rack is transmitted through
the track rods and track rod ends to the
steering arms, which are an integral part of
the strut housings.
On 5-Series models, the upper part of the
steering system is identical to a 3-Series.
Instead of a rack-and-pinion set-up, however,
these models use a power-assisted
recirculating ball steering box which steers
the front wheels via a steering linkage
consisting of a Pitman arm, an idler arm, a
centre track rod, a pair of inner track rods,
and two track rod ends.
10•12 Suspension and steering systems
15.14d When you refit the spacer, make
sure it’s centred on the inner race of the
bearing before tightening the nut15.14c Hold the stub axle flange with a
large lever while tightening the nut15.14b You can fabricate your own spacer
tool from a piece of 13 mm long, 38 mm
inside diameter pipe (left); you’ll also need
to use the old inner race (right)
15.14a To refit the new bearing, use a
large socket or a piece of pipe with an
outside diameter the same diameter as the
outer race of the bearing - don’t apply
force to the inner race - and make sure the
bearing is fully seated against the back of
its bore15.13b . . . then drive the bearing out of
the housing with a large socket or a
suitable piece of pipe15.13a Remove the large circlip that
retains the bearing in the housing . . .

Where power-assistance is fitted, hydraulic
pressure (provided by an engine-driven pump)
delivers power steering fluid to the rack-and-
pinion steering gear or the recirculating-ball
steering box - this enhances steering
response and reduces steering effort.
Aside from maintaining the proper level of
power steering fluid in the system and
checking the tension of the drivebelt (see
Chapter 1, where applicable), the steering
system requires no maintenance. However,
on high-mileage vehicles, the track rod end
balljoints, the universal joints on either end of
the universal joint shaft, and the rubber
coupling between the steering column and the
universal joint shaft will wear, develop
excessive play, and cause the steering to feel
somewhat loose. At this point, you’ll have to
renew these items; they can’t be serviced.
Before you conclude that the steering
system needs work, however, always check
the tyres (see Section 25) and tyre pressures
(see Chapter 1). Also inspect the bearings in
the strut upper mounts (see Section 5), the
front hub bearings (see Section 8) and other
suspension parts, which may also be
contributing to an imprecise steering feel.
17 Track rod ends-
removal and refitting
4
1Loosen but do not remove the wheel bolts,
then raise the front of the vehicle and secure it
on axle stands. Remove the front wheel.
3-Series models
2Loosen the nut on the track rod balljoint
stud, and free the balljoint stud from the
steering arm using a balljoint separator. In the
absence of a separator tool, try giving the
steering arm a few light blows with a hammer
(see illustration). Remove the nut, and
separate the balljoint stud from the steering
arm.3Loosen the clamp bolt that locks the track
rod end to the inner track rod. Measure the
length of the track rod end, or paint an
alignment mark on the threads to ensure the
track rod end is refitted in the same position
(see illustration). Unscrew the track rod end
from the inner track rod.
4Refitting is the reverse of removal. Make
sure the mark you made on the threads of the
track rod end is aligned correctly, if
applicable. If you measured the track rod end,
make sure it is refitted to the same distance.
5Have the toe-in checked and, if necessary,
adjusted at a dealer service department or
qualified garage.
5-Series models
6Measure the length of the track rod and
record your measurement, or paint an
alignment mark on the threads to ensure the
track rod end is refitted in the same position
(see illustration). Loosen the clamp bolt.
7Use a balljoint separator or a puller to
separate the track rod end from the steering
arm (see illustration).
8Unscrew the track rod end.
9Refitting is the reverse of removal. Make
sure you align the paint mark made on the
threads of the track rod end, if applicable. If
you measured the track rod end, make sure it
is refitted to the same distance.
10Have the toe-in checked and, if
necessary, adjusted at a dealer service
department or qualified garage.
18 Steering gear boots
(3-Series)- renewal
4
1Remove the track rod ends (see Sec-
tion 17).
2Cut the boot clamps at both ends of the old
boots, and slide off the boots.
3While the boots are removed, inspect the
seals in the end of the steering gear. If they’releaking, renew the steering gear (see Sec-
tion 19).
4Slide the new boots into place and fit new
boot clamps.
5Refit the track rod ends (see Section 17).
19 Rack-and-pinion steering
gear (3-Series)-
removal and refitting
4
Removal
1Loosen but do not remove the wheel bolts,
raise the vehicle and support it securely on
axle stands. Remove the front wheels.
2Mark the lower universal joint on the
steering shaft and the pinion shaft, to ensure
proper alignment when they’re reassembled.
Remove the nut and bolt that attach the lower
end of the universal joint shaft to the steering
gear pinion shaft. Loosen the bolt and nut at
the upper end of the universal joint shaft. Slide
the universal joint shaft up a little, disengage it
from the pinion shaft, and remove it. Inspect
the universal joints and the rubber coupling
for wear. If any of them are worn or defective,
renew the universal joint shaft.
3On power steering models, using a large
Suspension and steering systems 10•13
17.6 Measure the length of the track rod
and record your measurement, or paint an
alignment mark on the threads to ensure
the track rod end is refitted in the same
position, then loosen the clamp bolt
(arrowed)17.3 Loosen the clamp bolt (arrowed) that
locks the track rod end to the inner track
rod. Paint an alignment mark on the
threads, to ensure the track rod end is
refitted in the same position, and
unscrew the track rod end from the inner
track rod17.2 Loosen the nut on the track rod
balljoint stud. For preference use a
balljoint separator; otherwise, give the
steering arm a few light blows with a
hammer to release the balljoint stud.
Remove the nut, and separate the balljoint
stud from the steering arm
17.7 Using a puller to separate the track
rod end from the steering arm
10

syringe or hand pump, empty the power
steering fluid reservoir.
4On power steering models, remove the
banjo bolts and disconnect the power
steering pressure and return lines from the
steering gear. Place a container under the
lines to catch spilled fluid. Plug the lines to
prevent excessive fluid loss and
contamination. Discard the sealing washers
(new ones should be used when
reassembling).
5Disconnect the track rod ends from the
steering arms (see Section 17).
6Remove the nuts and bolts from the
steering gear mounting brackets (see
illustration). Discard the old nuts.
7Withdraw the assembly from beneath the
vehicle. Take care not to damage the steering
gear boots.
Refitting
8Refitting is the reverse of removal. Make
sure the marks you made on the lower
universal joint and the pinion shaft are aligned
before you tighten the clamping bolts for the
upper and lower universal joints. Use new
self-locking nuts on the steering rackmounting bolts, and new sealing washers on
the hydraulic line fittings. Tighten the
mounting bolts, the track rod end nuts and the
universal joint shaft clamping bolts to the
torque values listed in this Chapter’s Specifi-
cations.
9Lower the vehicle to the ground.
10On power steering models, fill the
reservoir with the recommended fluid (see
Chapter 1) and bleed the power steering
system (see Section 23).
11It’s a good idea to have the front wheel
alignment checked by a dealer service
department or qualified garage.
20 Steering linkage (5-Series)-
inspection, removal and
refitting
4
Inspection
1Raise the vehicle and place it securely on
axle stands.
2Firmly grasp each front tyre at the top and
bottom, then at the front and rear, and check
for play in the steering linkage by rocking the
tyre back and forth. There should be little or
no play in any of the linkage balljoints. Inspect
the Pitman arm, the idler arm, the centre track
rod, the inner track rods, the track rod ends
and the steering arms for any obvious
damage. Try forcing the linkage parts in
opposite directions from one another. There
should be no play between any of them. If any
of the parts are bent or damaged in any way,
or if any of the balljoints are worn, renew the
parts concerned.
Removal
3Before dismantling the steering linkage,
obtain a suitable balljoint separator. A two-jaw
puller or a wedge-type tool will work (although
the wedge-type tends to tear the balljoint
boots). Sometimes, you can also jar a balljoint
taper pin free from its eye by striking opposite
sides of the eye simultaneously with two large
hammers, but the space available to do this is
limited, and the balljoint stud sometimessticks to the eye because of rust and dirt.
There is also a risk of damaging the
component being struck.
4To remove the outer track rods, disconnect
the track rod ends from the steering arms (see
Section 17). Remove the nut that attaches the
balljoint on the inner end of each outer track
rod to the centre track rod (see illustration).
Using a balljoint separator, disconnect the
outer track rods from the centre track rod. If
you’re renewing the balljoint at either end of
the outer track rods, paint or scribe alignment
marks on the threads to mark their respective
positions as a guide to adjustment during
reassembly (see illustration 17.3).
5To remove the centre track rod, remove the
nuts that attach the centre track rod balljoints
to the Pitman arm and the idler arm, and use a
balljoint separator to disconnect the balljoints
from the two arms.
6To remove the Pitman arm, you’ll have to
remove the steering box first (see Section 21).
Look for match marks between the sector
shaft and arm. If there aren’t any, scribe a
mark across the bottom face of both parts.
Remove the Pitman arm pinch-bolt and nut,
then remove the arm with a puller.
7To unbolt the idler arm, first remove the
small cover bolted to the top of the subframe
crossmember. Put a spanner on the bolt, and
remove the nut recessed into the underside of
the subframe crossmember (see illustration).
Check the idler arm rubber bush for wear. If
it’s damaged or worn, renew it.
8Check each balljoint for excessive play or
stiffness, and for split or deteriorated rubber
dust boots. Renew all worn or damaged
balljoints. The inner and outer track rod ends
on the outer track rods can be renewed
individually; if either balljoint on the centre
track rod is damaged or worn, you must
renew the centre track rod.
Refitting
9Refitting is the reverse of the removal
procedure, but observe the following points:
a) Realign the match marks on the Pitman
arm and the steering box sector shaft
when reassembling them.
b) If you’re fitting new inner or outer track
rod ends on the outer track rods, position
them so that the match marks made
during dismantling are aligned, and make
sure they are equally spaced on each
side.
c) Position the track rod end balljoint studs
on the outer track rods at an angle of 90°
to each other.
d) Make sure the left and right outer track
rods are equal in length when they are
fitted.
e) Tighten all retaining bolts to the torque
values listed in this Chapter’s Specifi-
cations.
f) When reassembly of the linkage is
complete, have the front wheel alignment
checked, and if necessary, adjusted.
10•14 Suspension and steering systems
20.7 To unbolt the idler arm from the
subframe crossmember, remove this nut
(arrowed)
20.4 To remove an outer track rod,
remove this nut (arrowed) from the end of
the centre track rod, and use a balljoint
separator to separate the balljoint stud
from the centre track rod (if you’re
renewing the inner track rod end, mark the
threads with paint before loosening the
clamp bolt and nut)
19.6 Rack-and-pinion steering gear
mounting bolts (arrowed) - 3-Series
models - (self-locking nuts not visible in
this photo)

21 Steering box (5-Series)-
removal and refitting
4
Removal
Note:If you find that the steering box is
defective, it is not recommended that you
overhaul it. Because of the special tools
needed to do the job, it is best to let your
dealer service department overhaul it for you
(otherwise, fit a new unit). Removal and
refitting the steering box is outlined here.
1On 5-Series E28 (“old-shape”) models,
discharge the hydraulic system by depressing
the brake pedal about 20 times.
2Using a large syringe or hand pump, empty
the power steering fluid reservoir (see Chap-
ter 1).
3Raise the front of the vehicle and support it
securely on axle stands.
4Support the front of the engine with a trolley
jack. Place a block of wood between the jack
head and the sump to protect the sump from
damage.
5Remove the pivot bolts from the inner ends
of the front control arms (see Section 4).
6Remove the nuts from the left and right
engine mountings (see Chapter 2).
7Remove the mounting bolts (two on each
side on earlier models, three on each side on
later models) from the subframe crossmember
(see illustration)and remove the subframe.
8Remove the nuts and bolts that secure the
universal joint shaft to the steering box worm
shaft. Slide the universal joint shaft up and off
the worm shaft. Inspect the universal joint
shaft for wear. If it’s stiff or worn, renew it.
9Remove the banjo bolts, and disconnect
the hydraulic pressure line and the return line
from the box (see illustration). Plug the ends
of the lines to prevent fluid loss and
contamination. Discard the sealing washers -
new ones should be used when reassembling.
10Remove the steering box retaining bolts
(see illustrations)and remove the steering
box.
11If it’s necessary to detach the Pitman arm
from the box sector shaft (to have the box
serviced or to switch the arm to a new orrebuilt unit), make a match mark across the
two for correct reassembly. Remove the
Pitman arm retaining nut and washer. Use a
puller to withdraw the arm if necessary.
Refitting
12Refit the Pitman arm by aligning the
match marks made during removal, then
tighten the nut to the torque listed in this
Chapter’s Specifications.
13When fitted the Pitman arm must not have
any measurable endfloat within 100° from the
neutral position. If play exists, have the
following parts checked:
a) Sector shaft and bearings (for wear)
b) Thrust washer and adjuster bolt head (for
wear)
c) Ball nut and worm shaft (for wear)
14Refit the steering box. Align the mark on
the pinion gear shaft with the mark on the
universal joint shaft, and tighten the steering
box bolts to the torque listed in this Chapter’s
Specifications.
15The remainder of refitting is the reverse of
removal. Be sure to use new self-locking nuts
on the universal joint shaft, the centre track
rod, the steering box and the crossmember.
Also, use new sealing washers on the
hydraulic line fittings.
16Refer to Chapter 1 and fill the powersteering reservoir with the recommended
fluid, then bleed the system as described in
Section 23. Check for leakage from the lines
and connections.22 Power steering pump-
removal and refitting
1
Removal
1Raise the vehicle and support it securely on
axle stands. Remove the engine undertray.
2On 5-Series E28 (“old-shape”) models,
discharge the hydraulic system by depressing
the brake pedal about 20 times before
loosening the hydraulic line fittings.
3Disconnect the fluid return hose, and drain
the power steering fluid from the reservoir into
a clean container. Disconnect the pressure
line from the pump.
4If you need to remove the pulley from the
pump, push on the power steering pump
drivebelt by hand to increase the tension, and
unscrew the pulley nuts or bolts.
5Loosen the power steering pump drivebelt
tensioner bolt, and remove the drivebelt (see
Chapter 1).
6Remove the mounting bolts (see
illustrations)and detach the power steering
pump.
Suspension and steering systems 10•15
21.10a This bolt (arrowed) secures the
steering box to the subframe
crossmember. The nut, not visible in this
photo, is accessed through a hole in the
crossmember (engine removed for clarity,
left-hand-drive shown)21.9 Disconnect the power steering
pressure line fitting (right arrow) and the
return line fitting (left arrow). Note that the
return line fitting banjo bolt is larger than
the bolt for the pressure line fitting (left-
hand-drive shown)21.7 Subframe crossmember bolts
(arrowed)
22.6a Typical 3-Series power steering
pump adjusting bolt (arrowed) . . .
21.10b This bolt (arrowed) attaches the
steering box to the body (the nut, not
visible in this photo, is on the front side of
the steering box)
10

Refitting
7Refitting is the reverse of removal. Tighten
the nuts and bolts securely. Adjust the
drivebelt tension (see Chapter 1).
8Top-up the fluid level in the reservoir (see
Chapter 1) and bleed the system (see Sec-
tion 23).
23 Power steering system-
bleeding
1
1To bleed the power steering system, begin
by checking the power steering fluid level and
adding fluid if necessary (see Chapter 1).
2Raise and support the front of the vehicle
on axle stands.
3Turn the steering wheel from lock-to-lock
several times. Recheck the fluid level and top
up if necessary.
4Start the engine and run it at 1000 rpm or
less. Turn the steering wheel from lock-to-
lock again (three or four times) and recheck
the fluid level one more time. Note:On 5-Series E28 (“old-shape”) models, pump the
brake pedal five or six times before turning the
steering wheel. Once the fluid level remains
constant, continue turning the wheel back and
forth until no more bubbles appear in the fluid
in the reservoir.
5Lower the vehicle to the ground. Run the
engine and again turn the wheels from lock-
to-lock several more times. Recheck the fluid
level. Position the wheels straight-ahead.24 Steering wheel-
removal and refitting
1
Warning: If the vehicle is
equipped with an airbag, do not
attempt this procedure. Have it
performed by a dealer service
department or other qualified specialist, as
there is a risk of injury if the airbag is
accidentally triggered.
Caution: If the radio in your
vehicle is equipped with an anti-
theft system, make sure you have
the correct activation code
before disconnecting the battery.
Note: If, after connecting the battery, the
wrong language appears on the instrument
panel display, refer to page 0-7 for the
language resetting procedure.
Removal
1Disconnect the battery negative cable.
2Using a small screwdriver, prise off the
BMW emblem in the centre of the steering
wheel.
3Remove the steering wheel nut, and mark
the relationship of the steering wheel hub to
the shaft (see illustration).
4On all 3-Series models, and on 1986 and
later 5-Series models, turn the ignition key to
the first position to unlock the ignition lock.
5Remove the steering wheel from thesteering shaft. If the wheel is difficult to
remove from the shaft, use a steering wheel
puller to remove it - don’t hammer on the
shaft.
Refitting
6Refitting is the reverse of removal. Be sure
to align the match marks you made on the
steering wheel and the shaft. Tighten the
steering wheel nut to the torque listed in this
Chapter’s Specifications.
25 Wheels and tyres-
general information
1
Note:For more information on care and
maintenance of tyres, refer to Chapter 1.
1All vehicles covered by this manual are
equipped with steel-belted radial tyres as
original equipment. Use of other types or
sizes of tyres may affect the ride and handling
of the vehicle. Don’t mix different types or
sizes of tyres, as the handling and braking
may be seriously affected. It’s recommended
that tyres be renewed in pairs on the same
axle; if only one new tyre is being fitted, be
sure it’s the same size, structure and tread
design as the other.
2Because tyre pressure has a substantial
effect on handling and wear, the pressure on
all tyres should be checked at least once a
month or before any extended trips (see
Chapter 1).
3Wheels must be renewed if they are bent,
heavily dented, leak air, or are otherwise
damaged.
4Tyre and wheel balance is important in the
overall handling, braking and performance of
the vehicle. Unbalanced wheels can adversely
affect handling and ride characteristics, as
well as tyre life. Whenever a new tyre is fitted,
the tyre and wheel should be balanced.
10•16 Suspension and steering systems
24.3 After removing the steering wheel
nut, mark the relationship of the steering
wheel to the steering shaft (arrowed) to
ensure proper alignment during
reassembly
22.6c Typical 5-Series power steering pump mounting bolts
(arrowed)22.6b . . . and mounting nut and bolt (arrowed)

12
Chapter 12 Body electrical systems
Bulb renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Central locking system - description and check . . . . . . . . . . . . . . . . 20
Cruise control system - description and check . . . . . . . . . . . . . . . . 19
Direction indicator/hazard warning flasher - check and renewal . . . 5
Electric windows - description and check . . . . . . . . . . . . . . . . . . . . 21
Electrical system fault finding - general information . . . . . . . . . . . . . 2
Fuses - general information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
General information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Headlight housing - removal and refitting . . . . . . . . . . . . . . . . . . . . . 14
Headlights - adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Headlights - bulb renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12Heated rear window - check and repair . . . . . . . . . . . . . . . . . . . . . . 17
Ignition switch - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . 7
Instrument cluster - removal and refitting . . . . . . . . . . . . . . . . . . . . . 10
Radio - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Radio aerial - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Relays - general information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Service Indicator (SI) board - general information . . . . . . . . . . . . . . 11
Steering column switches - removal and refitting . . . . . . . . . . . . . . . 6
Supplemental Restraint System (SRS) - general information . . . . . . 18
Windscreen/tailgate wiper motor - removal and refitting . . . . . . . . . 16
Wiring diagrams - general information . . . . . . . . . . . . . . . . . . . . . . . 22
12•1
Easy,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 Contents
1 General information
The chassis electrical system of this vehicle
is of 12-volt, negative earth type. Power for
the lights and all electrical accessories is
supplied by a lead/acid-type battery, which is
charged by the alternator.
This Chapter covers repair and service
procedures for various chassis (non-engine
related) electrical components. For
information regarding the engine electrical
system components (battery, alternator,
distributor and starter motor), see Chapter 5.
Warning: To prevent electrical
short-circuits, fires and injury,
always disconnect the battery
negative terminal before
checking, repairing or renewing electrical
components.
Caution: If the radio in your
vehicle is equipped with an anti-
theft system, make sure you have
the correct activation code
before disconnecting the battery, Refer to
the information on page 0-7 at the front of
this manual before detaching the cable.
Note: If, after connecting the battery, the
wrong language appears on the instrument
panel display, refer to page 0-7 for the
language resetting procedure.
2 Electrical system fault
finding- general information
2
A typical electrical circuit consists of an
electrical component, any switches, relays,
motors, fuses, fusible links or circuit breakers,
etc related to that component, and the wiring
and connectors that link the components to
both the battery and the chassis. To help you
pinpoint an electrical circuit problem, wiring
diagrams are included at the end of this book.
Before tackling any troublesome electrical
circuit, first study the appropriate wiring
diagrams to get a complete understanding of
what makes up that individual circuit.
Troublespots, for instance, can often be
isolated by noting if other components related
to that circuit are routed through the same
fuse and earth connections.
Electrical problems usually stem from
simple causes such as loose or corroded
connectors, a blown fuse, a melted fusible
link, or a bad relay. Inspect all fuses, wires
and connectors in a problem circuit first.
The basic tools needed include a circuit
tester, a high-impedance digital voltmeter, a
continuity tester and a jumper wire with an in-
line circuit breaker for bypassing electrical
components. Before attempting to locate or
define a problem with electrical testinstruments, use the wiring diagrams to
decide where to make the necessary
connections.
Voltage checks
Perform a voltage check first when a circuit
is not functioning properly. Connect one lead
of a circuit tester to either the negative battery
terminal or a known good earth.
Connect the other lead to a connector in
the circuit being tested, preferably nearest to
the battery or fuse. If the bulb of the tester
lights up, voltage is present, which means that
the part of the circuit between the connector
and the battery is problem-free. Continue
checking the rest of the circuit in the same
fashion.
When you reach a point at which no voltage
is present, the problem lies between that point
and the last test point with voltage. Most of
the time, problems can be traced to a loose
connection.Note:Keep in mind that some
circuits receive voltage only when the ignition
key is turned to a certain position.
Electrical fault diagnosis is simple if you
keep in mind that all electrical circuits are
basically electricity running from the battery,
through the wires, switches, relays, fuses and
fusible links to each electrical component
(light bulb, motor, etc) and then to earth, from
where it is passed back to the battery. Any
electrical problem is an interruption in the flow
of electricity to and from the battery.

Finding a short-circuit
One method of finding a short-circuit is to
remove the fuse and connect a test light or
voltmeter in its place. There should be no
voltage present in the circuit. Move the
electrical connectors from side-to-side while
watching the test light. If the bulb goes on,
there is a short to earth somewhere in that
area, probably where the insulation has been
rubbed through. The same test can be
performed on each component in a circuit,
even a switch.
Earth check
Perform a earth check to see whether a
component is properly earthed (passing
current back via the vehicle body). Disconnect
the battery, and connect one lead of a self-
powered test light (often known as a
continuity tester) to a known good earth.
Connect the other lead to the wire or earth
connection being tested. The bulb should
light, indicating a good earth connection. If
not, dismantle the connection, and clean all
relevant parts thoroughly. When re-making
the connection, use serrated (shakeproof)
washers if possible, and tighten all bolts, etc,
securely.
Caution: If the radio in your
vehicle is equipped with an anti-
theft system, make sure you have
the correct activation code
before disconnecting the battery, Refer to
the information on page 0-7 at the front of
this manual before detaching the cable.
Note: If, after connecting the battery, the
wrong language appears on the instrument
panel display, refer to page 0-7 for the
language resetting procedure.
Continuity check
A continuity check determines if there are
any breaks in a circuit - if it is conducting
electricity properly. With the circuit off (no
power in the circuit), a self-powered continuity
tester can be used to check the circuit.
Connect the test leads to both ends of the
circuit, and if the test light comes on, the
circuit is passing current properly. If the light
doesn’t come on, there is a break somewhere
in the circuit. The same procedure can be
used to test a switch, by connecting the
continuity tester to the power-in and power-
out sides of the switch. With the switch turned
on, the test light should come on.
Finding an open-circuit
When diagnosing for possible open-
circuits, it is often difficult to locate them by
sight, because oxidation or terminal
misalignment are hidden by the connectors.
Intermittent problems are often caused by
oxidised or loose connections. Merely
wiggling an electrical connector may correct
the open-circuit condition, albeit temporarily.
Dismantle the connector, and spray with a
water-dispersant aerosol. On simpler
connectors, it may be possible to carefullybend the connector pins inside, to improve
the metal-to-metal contact - don’t damage
the connector in the process, however.
3 Fuses- general information
1
The electrical circuits of the vehicle are
protected by a combination of fuses and
circuit breakers. The fusebox is located in the
left corner of the engine compartment (see
illustration). On some later models, it is
located under the rear seat cushion.
Each of the fuses is designed to protect a
specific circuit, and on some models, the
various circuits are identified on the fuse
panel itself.
Miniaturised fuses are employed in the
fuseboxes. These compact fuses, with blade
terminal design, allow fingertip removal and
renewal. If an electrical component fails,
always check the fuse first. A blown fuse is
easily identified through the clear plastic
body. Visually inspect the element for
evidence of damage. If a continuity check is
called for, the blade terminal tips are exposed
in the fuse body.
Be sure to renew blown fuses with the
correct type. Fuses of different ratings are
physically interchangeable, but only fuses of
the proper rating should be used. Replacing a
fuse with one of a higher or lower value than
specified is not recommended. Each electrical
circuit needs a specific amount of protection.
The amperage value of each fuse is moulded
into the fuse body.
If the new fuse immediately fails, don’t
renew it again until the cause of the problem
is isolated and corrected. In most cases, the
cause will be a short-circuit in the wiring
caused by a broken or deteriorated wire.
4 Relays- general information
1
Several electrical accessories in the vehicle
use relays to transmit the electrical signal to
the component. If the relay is defective, thatcomponent will not operate properly. Relays
are electrically-operated switches, which are
often used in circuits drawing high levels of
current, or where more complex switching
arrangements are required.
The various relays are grouped together for
convenience in several locations under the
dash and in the engine compartment (see
accompanying illustration and illus-
tration 3.1).
If a faulty relay is suspected, it can be
removed and tested by a dealer or qualified
automotive electrician. No overhaul is
possible. Like fuses, defective relays must be
replaced with the correct type; some relays
look identical, but perform very different
functions.
5 Direction indicator/hazard
warning flasher unit- check
and renewal
2
Warning: Some later models are
equipped with an airbag or
Supplemental Restraint System
(SRS). To avoid possible damage
to this system, the manufacturer
recommends that, on airbag-equipped
models, the following procedure should be
left to a dealer service department, or
other specialist, because of the special
tools and techniques required. There is a
risk of injury if the airbag is accidentally
triggered.
1The direction indicator/hazard flasher unit is
a small canister- or box-shaped unit located
in the wiring harness on or near the steering
column. Access is gained by removing the
steering column shrouds (see illustration).
2When the flasher unit is functioning
properly, a regular clicking noise can be heard
from it when the indicators or hazard flashers
are switched on. If the direction indicators fail
on one side or the other, and the flasher unit
does not make its characteristic clicking
sound, a faulty direction indicator bulb is
indicated.
3If both direction indicators fail to blink, the
problem may be due to a blown fuse, a faulty
flasher unit, a broken switch or a loose or open
connection. If a quick check of the fusebox
12•2 Body electrical systems
4.2 Engine compartment relays3.1 The fusebox is located in the engine
compartment under a cover - the box also
includes several relays

8 Radio- removal and refitting
1
Caution: If the radio in your
vehicle is equipped with an anti-
theft system, make sure you have
the correct activation code
before disconnecting the battery, Refer to
the information on page 0-7 at the front of
this manual before detaching the cable.
Note: If, after connecting the battery, the
wrong language appears on the instrument
panel display, refer to page 0-7 for the
language resetting procedure.
Removal
1Disconnect the battery negative cable.
2The radios on most models are held in place
by internal clips which are usually located at
the sides or corners of the unit faceplate.
Removal requires a special tool which is
inserted into the holes to release the clips so
the radio can be pulled out. These tools can be
fabricated from heavy wire, or are available
from your dealer or a car audio specialist. On
anti-theft radios, the clips are moved in and
out by internal screws which require another
type of tool. Insert the tool into the holes until
the clips release, then withdraw the radio from
the dash panel. Disconnect the wiring from the
radio and remove it.3On some models, the radio is held in place
by screws located beneath the faceplate. The
control knobs must be pulled off before the
faceplate can be withdrawn.
Refitting
4Refitting is the reverse of removal.
9 Aerial- removal and refitting
1
Caution: If the radio in your
vehicle is equipped with an anti-
theft system, make sure you have
the correct activation code
before disconnecting the battery, Refer to
the information on page 0-7 at the front of
this manual before detaching the cable.
Note: If, after connecting the battery, the
wrong language appears on the instrument
panel display, refer to page 0-7 for the
language resetting procedure.
Removal
1Disconnect the battery negative cable.
2Use circlip pliers to unscrew the aerial
mounting nut.
3Open the boot lid/tailgate and remove the
left side trim panel. On some models, the jack
and tail light cluster cover will have to be
removed first.
4Unplug the aerial power and radio lead
connectors (as applicable), remove the
retaining bolts, and remove the aerial and
motor assembly.
Refitting
5Refitting is the reverse of removal.
10 Instrument cluster-
removal and refitting
2
Caution: The instrument cluster
and components are very
susceptible to damage from
static electricity. Make sure you
are earthed and have dischargedany static electricity (by touching an object
such as a metal water pipe) before
touching the cluster or components.
Caution: If the radio in your
vehicle is equipped with an anti-
theft system, make sure you have
the correct activation code
before disconnecting the battery, Refer to
the information on page 0-7 at the front of
this manual before detaching the cable.
Note: If, after connecting the battery, the
wrong language appears on the instrument
panel display, refer to page 0-7 for the
language resetting procedure.
Removal
1Disconnect the battery negative cable.
2As necessary, remove the steering column
shrouds and lower trim panel (see Chap-
ter 11).
3Remove the screws holding the cluster to
the facia (see illustration). Note the location
of the lower screws to ensure they are refitted
in the same place. On 3-Series models, the
length of the two lower inner screws must not
exceed 9.5 mm.
4Tilt the top of the cluster back, reach
behind it and detach the electrical connectors
by pressing on the levers, then lift the cluster
out of the facia opening (see illustration).
5For access to the cluster components,
release the catches or remove the screws,
and separate the two halves (see
illustration).
Refitting
6Refitting is the reverse of removal.
11 Service Indicator (SI) board-
general information
All models that have service indicator lights
are equipped with a Service Indicator (SI)
board located in the instrument cluster. This
board turns the lights on at the proper mileage
intervals. The lights can only be turned off
using a special tool which plugs into the
engine check connector (see Chapter 1). The
12•4 Body electrical systems
10.5 Turn the plastic knobs to release the
back of the cluster (some models use
screws)10.4 Push on the levers to detach the
cluster electrical connectors10.3 Use a Phillips screwdriver to remove
the instrument cluster retaining screws
7.5 Insert a screwdriver into the openings
(arrowed) on each side of the switch to
release the clip while pulling out