MG MGB User Manual

N
THE
ELECTRICAL
SYSTEM
and
the
light
signals
extinguished.
The
consequent
reduction
of electromagnetism
in
the
core
allows
the
secondary
armature
to
return
to
its
original
position
and
so
extinguish the
pilot
warning
light.
The above
sequence
of
operations
continues
to
be
repeated
until the
indicator
switch
is
returned
to
the
‘oft’
position.
Functions
of
warhing
lamp
The warning
lamp
not
only
serves
to
indicate
that the
■asher
unit
is
functioning
correctly, but
also
gives
a
warning
of
any
bulb
failure
occurring
in
the
external
direction
indicator lamps—since
a
reduction
in
bulb
current
■owing
through
the coil
reduces
the electromagnetic
effect
acting
on
the
secondary
armature
and
so
prevents
closure
of
the
pilot
light
contacts.
Checking
faulty
operation
In
the
event
of trouble
occurring
with
a
■ashing
light
direction
indicator
system
the
following
procedure
should
be
followed.
Check
with
a
voltmeter
between
the
■asher unit
terminal
‘B’
(or
‘+’) and
earth
that battery
voltage
is present.
Check
the
bulbs for
broken
■laments.
Refer
to
the
vehicle wiring
diagram
and
check
all
■asher
circuit
connections.
Check
the appropriate
fuse.
Switch
on
the
ignition.
Connect
together
■asher
unit
terminals
‘B’
(or
‘+’) and ‘L’
and
operate
the direction
indicator
switch.
If the
■asher
lamps
now
light,
the
■asher unit is
defective
and
must
be
renewed.
Maintenance
Flasher units cannot
be
dismantled
for
subsequent
reassembly.
A
defective
unit
must
therefore be
renewed.
When renewing
a
■asher unit
or
installing
a
■ashing
light
system
it is
advisable
to
test
the circuits
before connections
to
■asher
terminals
are
made.
When
testing
join
the
cables
normally
connected
to
those
terminals
(green,
green
with
brown,
and
light
green) together
and
operate
the direction
indicator
switch. In
the
event
of
a
wrong
connection
having
been
made,
the ignition
auxiliaries
fuse will
blow
but
no
damage
will
be
done
to
the
■asher
unit.
Section
N
.17
SWITCHES
Always
disconnect
the
batteries
before
removing
any
switches
and
refer
to
the
wiring
diagram
and
switch
contact
numbers
when
re■tting
switches.
Ignition/starter
switch
Disconnect
the
Lucar
connectors
and,
using
Service
tool
18G
671,
remove
the
bezel
lock
ring.
Withdraw
the
switch
assembly
from
the
rear
of the
fascia.
To
remove
the
locking
barrel
from
the
switch
body
insert
the
ignition
key
and
turn
the
switch
to
‘ON’
to
align
the
barrel retaining
plunger
with the
small hole
in
the
switch
body.
Using
an
awl, depress
the
plunger
and
withdraw
the
barrel
and key.
'Reverse
the
removal
and
dismantling
procedure
to
assemble
._
and
re■t the
switch.
,7
N24
Lighting,
wiper,
and
blower
switches
Disconnect
the Lucar
connectors
and,
using
Service
tool
180 671
,
unscrew
the bezel
lock
rings.
Remove
the
switches from
the
rear
of the
fascia.
To re■t
the switches
reverse
the
removal
sequence.
Panel and
map-reading
lamp
switches
The
panel
light switch
is
controlled by
a
rheostat-type
rotary
switch and the
map-reading light by
a
push-pull-type
switch.
To
remove
the switches
depress
the spring-loaded
plunger
in
the switch knobs
and withdraw
the knobs. Use Service
tool
18C 671
to
remove
the bezel
lock
rings
and
remove
the
switches from the
rear
of the
fascia panel.
Reverse
this
sequence
to
re■t the switches.
Directlbn
indicator
and
headlight
■asher
switch (GHN4
and
GHD4
cars).
Unscrew
the four
screws
securing
the
two
halves
of the
cowling
and
remove
the
cowling. Disconnect
the
switch
lead
connectors
and
remove
the
two
switch bracket
■xing
screws.
Reverse
this
sequence
to
re■t the
switch and
cowling but
ensure
that the locating pin
on
the
switch and
the
locating
peg on
the
cowling
are
correctly
aligned.
NOTE—When replacing
an
early
type
switch
with
one
using
spring-loaded metal
paws
and
spring
leaves,
a
square-headed
trip
stud
must
be
used. Set
the height
of the stud
to
between
1.177 and 1.187 in.
(29.9 and
30.45
mm.)
from the
underside
of
the column.
Dip
switch
(GHN4 and GHD4
cars)
The dip
switch
is
mounted
on
a
bracket secured
to
the
front pedal box by
two
screws.
Remove
the
screws
to
free the
switch and bracket, disconnect
the electrical
connections,
and
remove
the switch.
To
re■t the switch
reverse
the
removal
sequence.
Direction
indicator/headlamp
■asher/high—low
beam/horn
switch
(GHNS
and GHDS
cars)
Refer
to
the instructions given
for removing
and
re■tting
the direction
indicator
and
headlamp
■asher
switch
(GHN4
and GHD4
cars).
Section
N.l8
LOCATION AND
REMEDY
OF FAULTS
Although
every
precaution is
taken
to
eliminate
possible
causes
of trouble, failure
may
occasionally
develop
through
lack
of
attention
to
the
equipment
or
damage
to
the
wiring.
The
following
set-out
is
the
recommended
procedure
for
a
systematic
examination
to
locate
and
remedy the
causes
of
some
of the
more
usual
faults encountered.
The
sources
of trouble
are
by
no
means
always
obvious, and
in
some cases a
considerable
amount
of
deduction
from the
symptoms
is
needed
before the
cause
is
disclosed.
For
instance,
the
engine
might
not
respond
to
the
starter
switch;
a
hasty
inference would be
that the
starter
motor
is
at
fault.
However,
as
the
motor
is
dependent
on
the
battery
it
may
be
that the battery
is
exhausted.
“""mwxrmmmt‘v
‘Ssue
_

MG MGB Specifications

General

Brand	MG
Model	MGB
Category	Automobile
Language	English