1994 BMW 325i Page 600

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
.

WARNING

Your
common
sense,
good
judge-
ment,
and
general
alertness
are
cru-
cial
to
safe
and
successful
service
work
.
Befcre
attempting
any
work
on
your
BMW,
read
the
warnings
and
cautions
on
page
vi¡
and
the
copyright
page
at
the
frontof
the
manual
.
Review
these
warnings
and
cautions
each
time
you
prepare
to
workon

your
BMW
.
Please
also
read
any
warnings
and
cautions
that
accom-
pany
the
procedures
in
the
manual
.

Door
glass
See
Door
windows
Door
windows
general
information
512-1
front
door
window
(2-door
models)
adjusting
512-7
removing/installing
512-5
front
door
window
(4-door
models)
initíalizing
512-1
removing/installing
512-2
rear
door
window
(4-door
models)
removing/installing
512-4
fixed
glass,
removing/installing
512-
4
rear
vent
window
or
vent
latch,
replacing
(2-door
models)
512-11
window
regulator
and
motor,
removing/installing
512-12
window
regulator
service
512-12Doorcheck
See
DoorsDoor
handle
See
Centrallocking
and
anti-theft
Door
panel
See
Doors
Doors
general
information
411-1
door
adjustment
411-2door
check,
replacing
411-2
door
panels
411-3
doors411-1
front
orrear
door,removing/installing
411-1
front
door
panel,
removing/installing

411-3
rear
door
panel,
removing/installing
411-4
rearsidepanel,
removing/installing
(two-door
model)
411-4
Drive
axle
See
Rear
suspension
Driveability
troubleshooting

See
Engine-general
Driveshaft
general
information
260-1
center
bearing
assembly,
replacing
260-6
driveshaft,
aligning
260-3
driveshaft,
installing
260-4

Driveshaft
(cont
.)
driveshaft,
removing260-4
driveshaftservice
260-3
flex-disc,
replacing
260-5
front
centering
guide,
replacing
260-7
guibo
See
flex-disc
troubleshooting260-1

ECM
(engine
control
module)
pin
assignment
See
Fuel
injection
Electrical
circuit
See
Electrical
system-general
Electrical
component
locations
general
information
610-1
auxíliary
relay
panel
610-2
component
location
table
610-9
component
locations
610-3
fuse
position
tables
610-19
fuse
positions
610-1
relay
positions
610-2
splice
panel,
left
610-2
splice
panel,
right
610-3
Electrical
system-general
general
information
600-1
continuity,
checking
600-5
electrical
test
equipment
600-2
safety
precautions
600-1

short
circuits
600-5
short
circuit,
testing
with
ohmmeter
600-6
short
circuit,
testing
with
voltmeter
600-6
troubleshooting
600-3
voltage,
measuring600-4
voltage
and
polarity
600-1
voltage
and
voltage
drops
600-4
voltage
drop,
testing
600-4
wiring
codes
and
abbreviations
600-2
wiring
diagrams
600-2
wiring,
fuses
and
relays
600-1
Electrical
wiring
diagrams
general
information
ELE-1
wiring
diagrams
ELE-2
ABS
ELE-117

ABS/AST
ELE-120
airbag
(supplemental
restraint
system)
ELE-140
air
conditioning
and
heating
ELE-
129
anti-theft
(Alpine)
system
ELE-144
anti-theft
(EWS
II)
ELE-150
body
computer
module
ELE-176
charging
system
ELE-67
convertible
top
ELE-253
cruise
control
ELE-112
data
link
connector
ELE-86
engine
cooling
ELE-94
engine
management
ELE-70
exterior
lights
ELE-194
ground
distribution
ELE-35

headlights/foglights
ELE-180

INDEX
3

Electrical
wiring
diagrams
(cont
.)

heated
seats
ELE-245

horns
ELE-153
instrument
panel
ELE-165
interior
lights/illumination
ELE-211
lumbar
control
ELE-247
on-board
computer
ELE-173
park
ventilation
ELE-139
power
distribution
ELE-2
power
door
locks
ELE-226
power
mirrors
ELE-241
power
seats
ELE-243

power
sunroof
ELE-248

power
windows
ELE-231
radio/cassette/CD/speakers
ELE-
255
rear
window
defogger
ELE-160
shift
interlock
ELE-110
starting
ELE-63
transmission
electronics
ELE-96
warning
systems`
.
chimes
ELE-178
wiper/washer
ELE-154
Emergencies
See
Fundamentals
for
the
do-it-
yourself
owner
Engine-general
general
information
100-1
air
flow
measurement
and
vacuum
leaks
100-12
basic
engine
settings
100-11
basic
requirements
100-11
battery
voltage
100-12connecting
rods
and
pistons
100-1
cooling
system
100-5
cylinder
block
and
crankshaft100-1
cylinder
compression,
checking
100-6
cylinder
head
and
valvetrain
100-2
DISA
(dual
resonance
intake
system)
100-3,130-3
driveability
troubleshooting
100-8
engine
management
system
100-3
fuel
delivery
100-5
fuel
supply
100-14ground
connections
100-13
ignition
100-5
lubrication
system100-5
mechanical
troubleshooting
100-5
on-board
diagnostics
(OBD)
100-8
oxygen
sensors
100-11
preventive
maintenance
100-11
VANOS
(variable
valve
timing)
100-2warningsand
cautions
100-5
wiring
andharness
connections100-
13Engine
control
module
(ECM)
See
Fuel
injection
Engine
removal
and
installation
general
information
110-1
engine,
removing/installing(4-cylinder
engines)
110-1
engine,
removing/installing
(6-cylinder
engines)
110-4
Engine
coolant
temperature
(ECT)
sensor
See
Fuel
injection
Engine
hood
See
Fenders,
enginehood