1994 BMW 318i Engine harness

ENGINE
HOOD

Hood,
raising
to
service
position

CA
UTION-

Do
not
switch
on
the
windshield
wipers
wlth
the
engine
hood
raised
.
As
a
precaution,
remove
the
wiper
motor
fuse
.
See
610
Electrical
Compo-
nent
Locations
.

1
.
4-door
models
:
Open
hood
fully
.
Remove
bolt
from

hood
hinge
behind
hood
supports
(left
and
right)
.
Raise
hood
to
service
position
.
See
Fig
.
5
.

2
.
2-door
models
:
Open
hood
fully
.

Fig
.
5
.



Hood
support
bracket
boltto
be
removed
(A)
on
4-door
cars
.

Remove
bolts
at
left
and
right
hinges
.
Swing
bracket
in
direc-
tion
of
arrow
to
raise
hood
into
service
position
.

"
Remove
ground
cable
atright
hood
hinge
.

"
Whilean
assistant
supports
hood,
detach
both
hood

supportsfrom
hood
.

"
Remove
detent
screws
at
back
of
hood
hinges
.
See

Fig
.
6
.
"
Lift
hood
while
pulling
hinge
forward
.
Support
hood
at

higher
position
.

3
.
When
service
work
is
complete,
return
hood
to
lower

position
and
instaf
screws
or
bolts
.

FENDERS,
ENGINE
HOOD



410-
3

Fig
.
6
.



Torx
screw
at
base
of
hood
hinge
(arrow)
.

Hood,
removing
and
installing

0013147

1
.
Raise
hood
.
Where
applicable,
partially
remove
hood

acoustic
insulation
to
access
rear
of
hood
.
See
Fig
.
7
.

Fig
.
7
.



Hood
insulation
retainer
being
pried
out

3
.
Detachgas-charged
hood
supportsfrom
hood
.

CAUTION
-

The
hood
is
heavy
.
Before
removing
the
hood
sup-
ports
or
hood
retainingbolts,
be
sure
to
have
an
assistant
help
support
the
hood
.

0013148

2
.
Disconnect
washer
fluid
hoses
from
washer
nozzles
.

Where
applicable,
disconnect
electrical
harness
con-

nectors
fromheated
nozzles
.

ENGINE
HOOD

600
Electrical
System-General

GENERAL
.
...........
.
.
.
.
.
.
.
.
.
...
.
...
600-1

Voltage
and
Polarity
........
.
.
.
.
.
.
.
.....
600-1

Ming,
Fuses
and
Relays
............
.
.
.
.
600-1

Electrical
System
Safety
Precautions
...
.
.
.
.
600-1

Electrical
Test
Equipment
.....
.
.
.
....
.
.
.
.
600-2

WIRING
DIAGRAMS
..
.
.
.
.
.
.
.
.
.
........
600-2

Ming
Codes
and
Abbreviations
..
.
...
.
....
600-2

ELECTRICAL
TROUBLESHOOTING
..
.
..
600-3

Voltage
and
Voltage
Drops
..........
.
.
.
.
.
600-4

GENERAL



Electrical
System
Safety
Precautions

A
brief
description
of
the
principal
parts
of
the
electrical
sys-
tem
is
presented
here
.
Also
covered
here
are
basic
electrical
system
troubleshooting
tips
.

Voltage
and
Polarity

The
vehicle
electrical
system
is
a
12-volt
direct
current
(DC)
negative-ground
system
.
A
voltage
regulator
controls
system
voltage
at
approximately
the
12-volt
rating
of
the
battery
.
Al¡
circuits
are
grounded
by
direct
or
indirect
connection
to
the

negative
(-)
terminal
of
the
battery
.
A
number
of
ground
con-

nections
throughout
the
car
connect
the
wiring
harness
to

chassis
ground
.
These
circuits
are
completedby
the
battery

cable
or
ground
strap
between
the
body
and
the
battery
nega-

tive
(-)
terminal
.

Wiring,
Fuses
and
Relays

Nearly
all
parts
of
the
wiring
harnessconnect
to
compo-

nents
of
the
electrical
system
with
keyed,
push-on
connectors

that
lock
into
place
.
Notable
exceptions
arethe
heavy
battery

cables
and
the
starter
wiring
.
The
wiring
is
color-coded
for
cir-

cuitidentification
.

With
theexception
of
the
battery
charging
system,
most

electrical
power
is
routed
from
the
ignition
switch
or
the
bat-
tery
through
the
main
fuse/relay
panel,
located
in
¡he
left
rear

comer
of
the
engine
compartment
.
Fuses
are
color
coded
to

indicate
current
capacities
.

The
relays
and
control
units/modules
are
mounted
in
vari-

ous
places
throughout
the
vehicle
.
See610
Electrical
Com-

ponent
Locations
.

ELECTRICAL
SYSTEM-GENERAL
600-1

Voltage,
measuring
.
.
.
................
.
.
600-4

Voltage
drop,
testing
.
.
.....
.
.....
.
......
600-4

Continuity,
checking
..
.
...
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
600-5
Short
Circuits
.
.
.
.
.
.
.
.
.....
.
...
.
.
.
.
.
.
.
.
.
600-5

Short
circuit,
testing
with
ohmmete'r
.
.
.
.
.
.
.
.
.
600-6

Short
circuit,
testing
with
voitmeter
.
.
.
.
.
.
.
.
.
600-6

TABLES
a
.
Terminal
and
Circuit
Numbers
..............
..
.600-3
Please
read
the
following
warnings
and
cautions
before
do-
ing
any
work
on
your
electrical
system
.

WARNING
-

"
The
cars
covered
by
this
manual
are
equipped
with
aSupplemental
Restraint
System
(SRS)
that
automatically
deploys
one
or
more
airbags
.
Each
airbag
unit
houses
an
explosive
powerful
charge
.
Any
work
involving
the
SRS
system
should
only
be
performed
byan
authorized
BMW
dealer
.
Making
repairs
without
the
proper
knowledge
and
special
test
equipment
may
cause
serious
per-
sonal
injury
.
See
721
Airbag
System
(SRS)
.

"
The
ignition
system
of
the
car
operates
at
lethal
voltages
.
People
with
pacemakers
or
weak
hearts
should
not
expose
themselves
to
the
ignition
sys-
tem
.
Extra
caution
mustbe
taken
when
working
on
the
ignition
system
or
when
servicing
theen-
gine
while
it
is
runningor
the
key
is
on
.
See
120
Ignition
System
for
additional
ignition
system
warnings
and
cautions
.

"
Before
operating
the
starter
without
starting
the
engine
(as
when
making
a
compressfon
test),
dis-
able
the
ignition
system
as
described
in
120
Igni-
tion
System
.

"
Keep
hands,
clothing
and
other
objects
clear
of
the
electric
radiator
coollng
fan
when
working
on
a
warm
engine
.
The
fan
may
start
at
any
tíme,
even
when
the
ignition
is
switched
off
.

GENERAL

600-2



ELECTRICAL
SYSTEM-GENERAL

CAUTION
-

"
Always
turn
off
the
engine
and
disconnect
the

negative
()
cable
from
the
batterybefore
remov-

ing
any
electrical
components
.
Disconnecting
the

battery
may
erase
fault
code(s)
stored
in
control

module
memory
.
Check
for
fault
codes
using
spe-
cial
BMW
diagnostic
equipment
.

"
Prior
to
disconnecting
the
battery,
read
the
bat-

tery
disconnection
cautions
given
at
the
front
of

this
manual
onpage
viii
.

"
Connect
and
disconnect
ignition
system
wires,
multiple
connectors,
and
ignition
test
equipment
leads
only
while
the
ignition
is
off
.

"
Do
not
disconnect
the
battery
with
engine
run-

ning
.

"
Do
not
quick-charge
the
battery
(for
boost
start-
ing)
for
longer
than
one
minute,
and
do
not
ex-
ceed
16
.5
volts
at
the
battery
with
the
boosting
cables
attached
.
Wait
at
feast
one
minute
before
boosting
the
battery
a
second
time
.

"
Do
not
usea
test
famp
that
has
a
normal
incan-

descent
bulb
to
test
circuits
contafning
electronic
components
.
The
high
electrical
consumptionof
these
test
lamps
may
damage
the
components
.

"
Do
not
use
an
analog
meter
.
Use
onfy
a
digital
multimeter
.

"
Many
of
the
solid-state
modules
are
static
sensi-
tive
.
Static
discharge
will
permanently
damage
them
.
Always
handle
the
modules
using
proper
static
prevention
equipment
and
techniques
.

"
To
avoid
damaging
harness
connectors
or
relay
panel
sockets,
use
jumper
wires
with
flat-blade
connectors
that
are
the
same
size
as
the
connec-
tor
or
relay
terminals
.

"
Always
switch
a
digital
multimeter
to
the
appropri-
ate
function
and
range
before
making
test
con-
nections
.

"
Do
not
tryto
start
the
engine
of
a
carwhich
has
been
heated
above176°F
(80°C),
(for
example,
in
a
paint
dryingbooth)
.
Allow
it
to
cool
to
normal
temperature
.

"
Disconnect
the
battery
before
dolng
any
electric
welding
on
the
car
.

"
Do
not
wash
the
engine
while
it
is
runnfng,
or
any-
time
the
ignition
is
switched
on
.

WIRING
DIAGRAMS

Electrical
Test
Equipment

Many
of
the
electrical
tests
described
in
this
manual
call
for

measuring
voltage,
currentorresistanceusing
a
digital
multi-

meter
(DMM)
.
Digital
meters
are
preferred
for
precise
mea-

surements
and
for
electronics
work
because
they
are
generally
more
accuratethan
analog
meters
.
The
numerical

display
is
alsoless
likely
to
be
misread,
since
there
is
no
nee-

dle
position
to
be
misinterpreted
by
reading
at
an
angle
.

An
LED
test
light
is
a
safe,
inexpensive
tool
that
can
be
used

to
perform
many
simple
electrical
tests
that
would
otherwise

require
a
digital
multimeter
.
The
LED
indicates
when
voltage

is
present
between
anytwo
test-points
in
a
circuit
.

CA
UTION-

"
Choose
test
equipment
carefully
.
Use
a
digital

multimeter
with
at
leadt
10
megaohm
input
im-

pedance,or
an
LED
test
light
.
An
analog
meter
(swing-need1e)
ora
test
light
with
a
normal
incan-
descent
bulb
may
draw
enough
current
to
dam-
age
sensitive
electronic
components
.

"
An
ohmmeter
must
not
beused
to
measure
resis-
tance
on
solidstate
components
suchas
controlunits
or
time
delay
relays
.

"
Always
disconnect
the
battery
before
making
re-

sístance
(ohm)
measurements
on
the
circuit
.

WIRING
DIAGRAMS

The
wiring
diagrams
shown
in
Electrical
Wiring
Diagrams

have
been
specially
designed
to
enable
quick
and
efficientdi-

agnosis
and
troubleshooting
of
electrical
malfunctions
.

Wiring
Codes
and
Abbreviations

A
lot
of
information
is
included
in
each
wiring
diagram
if
you
know
how
to
read
them
.
Wire
colors
in
the
diagrams
are
ab-

breviated
.
Combined
color
codes
indicate
a
multi-colored
wire
.
For
example
the
code
BLU/RED
indicates
a
Blue
wire

with
a
Red
stripe
.

Many
electrical
components,
connectors,
fuses,
and

ground
locations
are
identified
using
a
unique
number
.
Each

of
there
numbers
corresponds
to
a
particular
part
in
the
circuit
commonly
found
in
Electrical
Wiring
Diagrams
.

610-4



ELECTRICAL
COMPONENT
LOCATIONS

--J
L
Windshield
washertank
&
pump

Fig
.
7
.



E36
engine
compartment
layout
.
M42
engine
compartment
shown
.

-,x
0013204

Fig
.
8
.
Control
modules
under
right
sideof
dash
.
Glove
compart-
ment
has
been
removed
.
For
module
identification,
see
Fig
.
9
.

COMPONENT
LOCATIONS

RSP
'I



4

ABS



Main
engine



Power
hydraulic
harness
distribution
control
unit



connector
I



box
oe

1
.
SRS
(Airbag)
control
module
(through
1993)
2
.
ABS/ASC+T
control
module
(as
applicable)
3
.
Central
locking
module
(through
1993)
4
.
Anti-theft
alarm
module
or
ZKE
IV
control
module
(from
1994)5
.
Rear
window
blower
relay
(convertible
models)6
.
Horn
relay
7
.
Wiper/washer
module
8
.
Rear
power
window
relay
(four-door
models)9
.
Luggage
compartment
lid
lock
relay
(convertible)
10
.
Cruise
control
module
EWS
II
control
module
(from
Jan
.
1995)
RSP
:
Right
splice
panel

0013215

Fig
.
9
.



Identificationof
control
modules
under
right
side
of
dash
.
Module
utilízation
varies
byyear
andmodel

1
.
Heater
valves
2
.
ABS
pedal
travel
sensor3
.
ABS
pump

Fig
.
10
.
Left
rear
of
engine
compartment
.

4
.
Main
engineharness
con-
nector
5
.
Power
distribution
box

ELECTRICAL
COMPONENT
LOCATIONS
610-5

0013202
0013226

Fig
.
11
.
M42
engine
idie
speed
control
valve
(arrow)
beneath
intake
manifold

0012421

Fig
.
12
.
M44
engine
intake
air
temperature
(¡Al)
sensor
in
air
filter
housing

Fig
.
13
.
M50/S50U
S
engine
intake
air
temperature
(IAT)
sensor
(1)
and
throttle
position
sensor
(2)
.

301180

0012724

Fig
.
14
.
M52/S52U
S
engine
intake
air
temperature
(IAT)
sensor
in
bot-
tom
of
intake
manifold
(throttle
housing
shown
removed)
.

COMPONENT
LOCATIONS

610-6



ELECTRICAL
COMPONENT
LOCATIONS

Fig
.
15
.
M44
engine
harness
connectors
atair
intake

0011644
Fig
.
16
.
A/
C
recharging
ports
(arrows),
right
rear
of
engine
compart-ment

COMPONENT
LOCATIONS

0012427

811004

Fig
.
17
.
Six-cylinder
ignition
coil
in
top
of
cylinder
head
(M52
engine)
.

Fig
.
18
.
Cooling
fan
dualswitch
in
radiator
(arrow)
.

0013203

611-
4



WIPERS
AND
WASHERS

2
.
Remove
wiper
arms
as
described
earlier
.

3
.
Place
engine
hood
in
service
position
.
See
410
Fend-

ers,
Engine
Hood
.

4
.
Unclip
engine
bulkhead
plenum
grille
at
base
of
wind-

shield
and
pulí
it
away
from
rubbergasket
.
See
Fig
.
5
.

Fig
.
5
.



Detach
grill
clips
(arrows)
and
pull
upward
.

0012527

5
.
Remove
wiring
harness
retaining
clip
frombulkhead
in
rear
of
engine
bay
.
Remove
screws
retaining
wiring
harness
protective
cover
.
See
Fig
.
6
.

0012529

Fig
.
6
.



Engine
bulkhead
wiring
harness
cover
screws
(arrows)
.

WINDSHIELD
WIPER
ASSEMBLY

Fig
.
7
.



Right
side
plenum
retaining
screws
(arrows)
.

7
.
On
driver's
side
of
air
plenum,
push
aside
wiring
har-

ness
and
remove
screw
retaining
plenum
.
Pull
plenum

up
andremove
from
engine
compartment
.
See
Fig
.
8
.

001¿534

Fig
.
8
.



Remove
screw
at
A
and
pull
plenum
housing
upward
.

8
.
On
6-cylinder
models
:
Remove
plastic
top
engine
cov-
ers
.
See
110Engine
Removal
and
Installation
.

NOTE-

Cover
ínside
edges
of
cowlpanelsheet
metal
with
thick
tape
to
prevent
damage
during
wiper
assembly
remov-
al
.

9
.
Remove
large
nut
and
washer
at
base
of
wiper
arm

shafts
cowi
panel
.
See
Fig
.
9
.

10
.
Remove
wiper
assembly
support
.
See
Fig
.
10
.

6
.
On
passenger
side
of
air
plenum,
push
aside
wiring



11
.
Separateharness
at
bulkhead
connector
.
See
Fig
.
11
.

harness
and
remove
twoscrews
retaining
plenum
housing
.
See
Fig
.
7
.



12
.
Wrap
protective
tape
around
wiper
shaft
on
driver's
side
to
prevent
damaging
painted
metal
during
remov-
al
.

Fig
.
9
.



Wiper
shaft
nut
at
cowl
(arrow)
.

Fig
.
10
.
Wiper
assembly
support
bolts
(arrows)
.

0012533
0012535

Fig
.
11
.
Wiper
assembly
electrical
connector
(arrow)
.

0012536

13
.
Push
wiper
arm
shaft
down
into
cowl
area
and
maneu-

ver
wiper
assembly
out
of
cowl
.

WIPERS
AND
WASHERS



611-
5

14
.
Installation
is
reverse
of
removal,noting
the
following
:

"
Install
all
fasteners
finger-tight
first
.

"
Once
installed,
wiper
motor
should
first
be
run
to

parked
position
and
switched
off
.

"
Next,
instaf
wiper
arms
butnotblades
.

"
Close
hood
and
fit
wiper
blades
.

"
Check
all
electrical
harness
fittings
and
sealing
grom-

mets
for
correct
reinstallation
.
Replace
any
wire
ties

cut
off
during
removal
.

Tightening
Torques

"
Wiper
shaft
nut
at
cowl
.............
12
Nm
(9
ft-Ib)

"
Wiper
support
to
wiper
assembly

orto
body
..
..
..
.
...............
10
Nm
(89
in-lb)

"
Wiper
arm
to
wiper
shaft
..........
25
Nm
(18
ft-lb)

Windshieldwiper
assembly,
removing
and

installing
(2-door
modeis)

NOTE-

The
wiper
arms
should
be
in
the
parked
position
before
removing
the
wiper
assembly
.
To
avoid
damaging
the
wiper
arms
and
pivots,
donotmanually
sidde
or
force
the
wiper
arm
across
the
windshield
.

1
.
Disconnect
negative
(-)cablefrom
battery
.

CAUTION-

"
Prior
to
disconnectiog
the
battery,
read
the
bat-
tery
disconnection
cautionsgiven
at
the
front
of
this
manual
on
page
viii
.

"
Use
fendercover
to
protect
windshield
.

2
.
Remove
wiper
arms
as
described
earlier
.

3
.
Place
engine
hood
in
service
position
.
See410
Fend-

ers,
Engine
Hood
.

4
.
Remove
trim
retainers
at
left
and
right
side
and
remove

air
plenum
grill
.
See
Fig
.
12
.

5
.
Remove
screws
retaining
wiring
harness
protective

cover
.
See
Fig
.
13
.

6
.
On
passenger
side
of
air
plenum,push
aside
wiring

harness
and
remove
two
screws
retaining
plenum

housing
.
See
Fig
.
14
.

WINDSHIELD
WIPER
ASSEMBLY