1985 FORD GRANADA audio

The electrical system is a 12 volt, negative
earth type. Electricity is generated by an
alternator, belt-driven from the crankshaft pulley.
A lead-acid 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.
Although some repair procedures are given
in this Chapter, sometimes renewal of a well-
used item will prove more satisfactory. The
reader whose interests extend beyond
component renewal should obtain a copy of
the “Automobile Electrical Manual”, available
from the publishers of this book.
Before starting work on the electrical
system, read the precautions listed in “Safety
first!” at the beginning of the manual.
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 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
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.
5To find the source of an intermittent wiring
fault (usually due to a poor or dirty connection,
or damaged wiring insulation), an integrity testcan be performed on the wiring, which
involves moving 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.
6Apart from problems due to poor
connections, two basic types of fault can
occur in an electrical circuit - open-circuit or
short-circuit.
7Open-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, but will
not cause the relevant circuit fuse to blow.
8Short-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. Note: A short-
circuit that occurs in the wiring between a
circuit’s battery supply and its fuse will not
cause the fuse in that particular circuit to blow.
This part of the circuit is unprotected - bear
this in mind when fault-finding on the vehicle’s
electrical system.
Finding an open-circuit
9To check for an open-circuit, connect one
lead of a circuit tester or voltmeter to either the
negative battery terminal or a known good earth.
10Connect the other lead to a connector in
the circuit being tested, preferably nearest to
the battery or fuse.
11Switch on the circuit, bearing in mind that
some circuits are live only when the ignition
switch is moved to a particular position.
12If voltage is present (indicated either by
the tester bulb lighting or a voltmeter reading,
as applicable), this means that the section of
2Electrical fault-finding - general
information
1General information
Body electrical system 13•3
13
Other relays and modules (continued)
IdentificationFunction
Behind facia (passenger side) (continued):
M4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Heated windscreen (timer)
M5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Air conditioning cooling fan
M6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .ABS pump relay
M7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .ABS main relay
M8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .ABS control unit
M9 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Ride height control
Below instrument panel (driver’s side):
N1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Bulb failure warning unit
Below facia (passenger side):
P1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .ABS module
P2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Fuel-injection system module
Behind facia (passenger side):
R1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Speed control system module
R2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Auxiliary warning system module
R3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Rear audio console module
Torque wrench settingsNmlbf ft
Alternator adjusting strap:
To steering pump bracket (SOHC) . . . . . . . . . . . . . . . . . . . . . . . . . . .21 to 2616 to 19
To front cover (V6) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41 to 5130 to 38
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Footwell lights
11Free the light unit by carefully prising with
a screwdriver(see illustration).
12Extract the bulbholder by twisting and
pulling. Renew the bulb, refit the holder and
press the light unit home.
Luggage area light
13Carefully prise free the light unit (see
illustration).
14Pull out the old bulb, press in the new one
and refit the light unit.
Engine bay light
15This light bulb is directly accessible once
the bonnet is opened. It is of the bayonet type.
Instrument panel lights
16Remove the instrument cluster.
17Extract the appropriate bulb and holder by
twisting it 90°anti-clockwise (see
illustration).
18Large bulbs are of the wedge base typeand can be pulled out of their holders. Small
bulbs and holders cannot be separated, but
must be renewed complete.
19Refit the bulbs and holder, then refit the
instrument panel.
Switch illumination lights
20The pilot lights in the minor switches cannot
be renewed independently of the switch.
21The bulbs which illuminate the lighting
master switch and the heater blower switch
can be renewed after pulling off the switch
knob (see illustration).
22The switch symbols in the instrument
panel surround are illuminated by a single
bulb. To gain access to the bulb, remove the
instrument panel surround, which is secured
by four screws. The bulb is of the wedge base
type (see illustration).
Glovebox light
23Open the glovebox. Remove the
combined switch/light unit, which is secured
by two screws (see illustration).
24Prise out the switch, renew the bayonet
fitting bulb and refit the switch
25Refit and secure the light unit with the two
screws.
Ashtray light
26Remove the storage box or audio unit
from just above the ashtray (see illustration).
27Free the bulbholder from above the ashtray,
either by pulling it outwards (low series trim) or
by carefully prising it away from its housing
using a screwdriver (high series trim).28Renew the wedge base bulb. Refit the
bulbholder and the other disturbed
components.
Radio fader light
29Carefully prise off the fader surround.
30Extract the bulbholder by twisting it anti-
clockwise. Disconnect its wiring plug and
remove it.
31The bulb and holder cannot be separated.
Fit the new bulbholder unit, check for correct
operation, then refit the fader surround.
Heater control light
32Remove the instrument panel surround.
33Pull off the heater control knobs, then
prise the display panel off the heater controls
to expose the bulb.
13•8Body electrical system
6.21 Pull off the switch knob to expose the
bulb
6.26 Ashtray light bulb seen through radio
aperture6.22 Removing the switch symbol
illumination light6.23 The glovebox light unit
6.13 Luggage area light unit6.17 Instrument panel lights
6.11 Footwell light bulb renewal - front (A)
and rear (B)
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Speed control module
Models before April 1992
9Refer to Section 27. The speed control
module shares the same mountings as the
AWS module; the AWS module is larger.
Models from April 1992
10The speed control module fitted to these
models is situated behind the glovebox on the
left-hand side of the facia. To gain access to
the module remove the left-hand facia
undercover panel. The speed control module
is vertically mounted just to the right of the
engine management module. Push the module
upwards to release the retaining clips then
lower it out from under the facia and
disconnect the wiring connector (see
illustration).
11Refitting is a reverse of the removal
procedure ensuring that the module is
securely retained by the retaining clips.
Vacuum pump
12The vacuum pump is located behind the
left-hand headlight on carburettor models, and
behind the right-hand headlight on fue-
injection models. Start by removing the
appropriate headlight unit.
13Disconnect the multi-plug and the vacuum
hose from the pump. The multi-plug is
released by squeezing and pulling it at the
same time.
14Prise out the three mountings and remove
the pump.
15When refitting, pull the pump mountings
into position with pliers. 16Reconnect the vacuum hose and the
multi-plug, then refit the headlight unit.
Vacuum servo
17Disconnect the servo-to-throttle linkage
cable at one end.
18Disconnect the vacuum hose from the
servo.
19Undo the servo retaining nut and remove
the servo from its bracket.
20Refit by reversing the removal operations.
On all but 2.0 litre carburettor models, adjust
the cable so that it is slightly slack when the
throttle linkage is in the idle position (pedal
released).
21On 2.0 litre carburettor models, the
stepper motor plunger must be withdrawn
before the cable is adjusted. Proceed as
follows.
22Observe the stepper motor plunger. Have
an assistant switch on the ignition for a few
seconds, then switch it off again. When the
ignition is switched off, the stepper motor
plunger will retract fully (“vent manifold”
position). Disconnect the battery negative lead
while the stepper motor plunger is retracted.
23Adjust the servo cable so that it is slightly
slack, then reconnect the battery negative
lead.
Printed circuit board
24The printed circuit board is located in the
steering wheel. It can be removed after
detaching the horn contact plate and
disconnecting the switch spade terminals as
described at the beginning of this Section.1Disconnect the battery negative lead.
2Pull off the rubber sealing strip from the top
of the plenum chamber (see illustration).
3Pull the two wiring harness clips from the
front of the plenum chamber (see illustration).
4Remove the two screws and two clips
which secure the plenum chamber cover (see
illustration). Lift out the cover.
5Disconnect the multi-plug from the blower
motor resistor. Also disconnect the motor
earth cable (see illustration).
6Remove the two nuts which secure the
motor assembly. Lift out the motor, casing and
resistor together.
7The casing halves and the resistor can be
separated from the motor after prising open
the clamp which holds the casing halves
together.
8Refit by reversing the removal operations.
1Two DIN standard extraction tools will be
needed to remove the radio/cassette unit.
These tools are available from vehicle audio
equipment specialists.
Radio (only)
2Pull off the control knobs, remove the
spindle nuts and washers and remove the
radio face plate.
3Push the two securing lugs inwards, at the
same time pulling the radio from its location.
The services of an assistant may be required.
4Withdraw the radio and disconnect the
aerial cable and the other wiring plugs from it.
5If a new radio is to be fitted, transfer the
support brackets and locating plate from the
old unit to the new one.
6Refit by reconnecting the wiring to the radio,
then sliding it into its aperture. Press it in until
the securing lugs click into position.
7Refit the face plate, spindle nuts and washers
and control knobs. The top of the face plate is
marked on the side which faces the radio.
30Radio or radio/cassette
player (original equipment) -
removal and refitting
29Heater blower motor -
removal and refitting
13•20Body electrical system
28.10 Removing the speed control module
29.4 One of the plenum chamber cover
clips29.5 Blower motor showing wiring
connections
29.2 Pulling off the rubber sealing strip29.3 Pulling out a wiring harness clip
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