1993 BMW 325i Workshop Manual

Continuity,
checking
Short
Circuits

from
Battery

CAUTION-

Use
only
a
high
quality
digital
ohmmeter
having
high
input
impedance
when
checking
electronic
componente
.
The
internal
power
source
used
in
most
analog
(swing-need1e)
meterscan
damage
solidstate
components
.

0013239

Fig
.
2
.



Digital
multimeter
being
used
to
check
for
voltage
drop
across
a
switch
.

The
continuity
test
can
beused
to
check
a
circuit
or
switch
.
Because
most
automotive
circuits
are
designed
to
have
little

or
no
resistance,
a
circuit
or
part
of
a
circuit
canbe
easily

checked
for
faults
using
an
ohmmeter
.
An
open
circuit
or
a
cir-

cuit
withhigh
resistance
will
not
allow
current
to
flow
.
A
círcuit
with
little
or
no
resistanceallows
current
to
flow
easily
.

When
checking
continuity,
the
ignition
should
be
off
.
On
cir-
cuits
that
are
powered
at
all
times,
the
battery
should
be
dis-
connected
.
Using
the
appropriate
wiring
diagram,
a
circuit
can
be
easily
tested
for
faulty
connections,
wires,
switches,
relays,
and
engine
sensorsby
checking
forcontinuity
.
For
a
continu-
ity
check
on
a
brake
light
switch,
see
Fig
.
3
..

A
short
circuit
is
exactly
what
the
narre
implies
.
The
circuit
takes
a
shorter
paththan
it
was
designed
to
take
.
The
most

common
short
that
causes
problems
is
a
short
to
ground

where
the
insulation
on
a
positive
(+)
wire
wears
away
and
the

metal
wire
is
exposed
.
When
the
wire
rubs
against
a
metal

partof
thecar
or
other
ground
source,
the
circuit
is
shorted
to
ground
.
If
the
exposed
wire
is
live
(positive
battery
voltage),
a

Puse
will
blow
and
the
circuit
may
possibly
be
damaged
.

ELECTRICAL
SYSTEM
-
GENERAL
600-
5

Brake
light
switch

Brake
pedal
in
rest
position

Q

Brake
pedal
depressed
Brake
light
switch

Fig
.
3
.



Brake
light
switchbeing
tested
for
continuity
.
With
brake
ped-
alin
rest
position
(switch
open)
there
is
no
continuity
(infinite
ohms)
.
With
pedal
depressed
(switch
closed)
there
is
continu-
ity
(zero
ohms)
.

Shorts
to
groundcanbe
located
with
a
digital
multimeter
.
Short
circuits
are
often
difficult
to
locate
and
may
vary
in
na-
ture
.
Short
circuits
can
befound
using
a
logical
approach
based
onthe
current
path
.

CAUTION
-

"
On
circuits
protected
with
high
rating
fuses
(25
amp
and
greater),
the
wires
or
circuit
compo-
nents
may
be
damaged
before
the
fuse
blows
.
Always
check
for
damage
before
replacing
fuses
of
this
rating
.

"
When
replacing
blown
fuses,
use
only
fuses
hav-
ingthe
correct
rating
.
Always
confirm
the
correct
fuse
rating
printed
on
the
fuselrelay
panelcover

DC

ELECTRICAL
TROUBLESHOOTING

00-
6



ELECTRICAL
SYSTEM-GENERAL

Short
circuit,
testing
with
ohmmeter



Short
circuit,
testing
with
voltmeter

1
.
Remove
blown
fuse
from
circuit
and
disconnect
cables



1
.
Remove
blown
fusefrom
circuit
.

from
battery
.
2
.
Disconnect
harness
connector
from
circuifs
loador

2
.
Disconnect
harness
connector
from
circuit's
loador



consumer
.

consumer
.

3
.
Using
an
ohmmeter,
connect
one
test
lead
to
loadside

of
f
use
terminal
(terminal
leading
to
circuit)
and
the
oth-

ertest
lead
to
ground
.
See
Fig
.
4
.

Load
disconnected
from
Battery

LO

n
I



~



Shotrouit
vu
.uto
earthth

Switch

Load

0013241

Fig
.
4
.



Digital
multimeter
being
usedasan
ohmmeter
to
find
short

circuit
.

4
.
lf
there
is
continuity
to
ground,
there
is
a
short
to

ground
.

ELECTRICAL
TROUBLESHOOTING

NOTE-

Most
fuses
power
more
than
one
consumer
.
Be
sure
aff

consumers
are
disconnected
when
checking
for
a
short
circuit
.

3
.
Using
a
voltmeter,
connect
test
leads
across
f
use
termi-

nals
.
See
Fig
.
5
.
Make
sure
power
is
present
ín
circuit
.

lf
necessary
turn
keyon
.

~2
.U

from
Battery

Load
disconnected

Short-circuit
to
earth

I



Fuse
box

0013240

5
.
If
there
is
no
continuity,
work
from
wire
harness
hearest



Fig
.
5
.



Digital
multimeter
being
usedas
a
voltmeter
to
find
short
cir

to
fuse/relay
panel
and
move
or
wiggle
wireswhile
ob-



cuit
.

serving
meter
.
Continue
to
movedown
harness
until

meter
displays
a
reading
.
This
is
the
location
of
short
to



4
.
lf
voltage
is
present
at
voltmeter,
there
is
a
short
to

ground
.



ground
.

Visually
inspect
the
wire
harness
at
this
point
for
any
faults
.



5
.
lf
voltage
is
not
present,
work
from
wire
harness
near-

If
no
faults
are
visible,
carefully
slice
open
the
harnesscover



est
to
fuse/relay
panel
and
move
orwiggle
wireswhile

or
the
wire
insulation
for
further
inspection
.
Repair
any
faults



observing
meter
.
Continue
to
move
down
harness
until
found
.



meter
displays
a
reading
.
This
is
the
location
of
short
to

ground
.

6
.
Visually
inspect
wire
harness
atthis
point
for
any
faults
.

lf
no
faults
are
visible,
carefully
slice
open
harness
cov-
erorwire
insulation
for
further
inspection
.
Repair
any

faults
found
.

610
Electrical
Component
Locations

GENERAL
...........
.
.
.
.
.
.
.
.
.
........
610-1



FOSE
POSITION
TABLES
..
.
.
.
.
.
.....
.
610-19

FUSE
AND
RELAY
POSITIONS
.
...
.
.
.
.
.
610-1

Fuse
Positions
.
.
.
................
.
.
.
.
.
610-1

Relay
Positions
.
.
.
.....
.
.
.
........
.
.
.
.
.
610-2

Auxiliary
RelayPanel
.....
.
...
.
........
.
610-2

SplicePanel,
Left
.
.
.
...
.
.
.
...
.
........
.
610-2

SplicePanel,
Right
.
.
.
.
.
.
.
.
...
.
.........
610-3

COMPONENT
LOCATIONS
.
.
.
.
.......
.
.610-3

Component
Location
Table
.
.
.
.
.
.
.........
610-9

GENERAL



FUSE
AND
RELAY
POSITIONS

This
repair
group
covers
f
use,
relay,
and
control
module
lo-



The
front
power
distribution
box,
an
auxiliary
relay
panel,cation
information
.
Electrical
equipment
and
accessories
in-



and
two
auxiliary
splice
panels
contain
most
of
the
fuses
and
stalled
varies
depending
on
model
and
model
year
.
Always



relays
in
E36
vehicles
.
Refer
to
the
component
location
later

confirm
that
the
proper
electrical
component
has
been
identi-



in
this
section,
as
well
as
the
tables
at
the
end
of
this
repair

fied
by
using
the
electrical
wiring
diagrams
.



group
for
electrical
component
location
.

WARNING
-

On
cars
equipped
with
airbags,
special
precautionsapply
to
any
electrical
system
testing
orrepair
.
Air-
bag
units
areexplosive
devices
and
mustbe
han-
dled
with
extremecare
.
Before
starting
any
work
onan
airbag
equipped
car,
refer
to
the
wamings
and
cautions
in
721
Airbag
System
(SRS)
.

CAUTION
-

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

"
Relay
and
fuse
positions
are
subject
to
changeand
may
varyfrom
car
to
car
.
If
questions
arise,
an
authorized
BMW
dealer
is
the
best
source
for
the
most
accurate
and
up-to-date
information
.

"
A
good
way
to
verify
a
relay
position
isto
com-
pare
the
wiring
colors
at
the
relay
socket
to
thecolors
indicated
on
the
wiring
diagrams
located
at
the
rear
of
this
manual
.

"
Always
switchthe
ignition
off
and
disconnect
the
negative
(-)
battery
cable
before
removing
any
electrical
components
.

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

"
Only
usea
digital
multimeter
for
electrical
tests
.

ELECTRICAL
COMPONENT
LOCATIONS



610-1

TABLES
a
.
E36Component
Locations
...........
.
.
..
...
610-10b
.
1992
E36
Fuse
Positions
..........
..
.
.
.....
610-20c
.
1993
E36
Fuse
Positions
..........
..
..
.
....
610-22d
.
1994
E36
Fuse
Positions



.........
...
.......
610-24e
.
1995
E36
Fuse
Positions
.........
...
.......
610-26
f
.



1996
E36
Fuse
Positions



.........
...
.......
610-28g
.
1997-1998
E36
Fuse
Positions
..
.
..
...
.......
610-30

Fuse
Positions

CAUTION
-

"
Replace
fuses
with
those
of
the
same
rating
.
In-
stalling
a
fuse
with
higher
rating
can
lead
to
cir-
cuit
failure
and
may
also
start
a
fire
.

"
Relay/fuse
positions
vary
by
model
and
equip-
ment
.

Fuses
number
1
through
46
are
mounted
in
the
front
power

distribution
box
.
See
Fig
.
1.

Fuses
31-46

~
Illlllllllll

°
-
Ilmmlmomlmoi

Fuses
1-20

(a
1
:1
E
El

~
~O!7

L~~n

4~
i
Fuses
21-30

Fig
.1.



Fuse
positions
1-46
in
front
power
distribution
box
.

0013034

FUSE
AND
RELAY
POSITIONS

610-2



ELECTRICAL
COMPONENT
LOCATIONS

Fuses
number47
and
50are
mounted
on
the
left
side
splice

panel
.
Refer
lo
Fig
.
5
.

Fuse48
is
mounted
on
the
auxiliary
relay
panel
.
Refer
to

Fig
.
3
.

Fuse
49
is
mounted
in
the
right
side
of
the
luggage
compart-

ment
behind
the
trim
cover
.

Relay
Positions

Mounted
in
the
left-hand
rear
comer
of
the
engine
compart-

ment,
the
power
distribution
box
contains
46
(uses
and
15
re-

lay
positions
.
See
Fig
.
2
.

Fuses31-46

-
Er
a
&QT
MM
~

Fig
.
2
.



E36
front
power
distribution
box
.

FUSE
AND
RELAY
POSITIONS

Fuses1-20

13
EL1
5
]

mmmmmmmmmm
Fuses
21-30
--



0013034)

1
.
Fuel
pump
relay



9
.



Heater/A/C
Blower
relay
2
.
System
(main)
relay



10
.



Rear
defogger
relay
3
.
Oxygen
sensorheater
re-



11
.
ABS
system
relay
lay



12
.
ABS
pump
relay
4
.



Horn
relay



13
.



High
speed
radiator
fan
re-
5
.



Taillight/foglight
relay



]ay
6
.
Low
beam
relay



14
.
A/C
compressor
relay
7
.



High
beam
relay



15
.



Low
speed
radiator
fan
re-
8
.



Emergency
flasherrelay



¡ay

Auxiliary
Relay
Panel

The
auxiliary
relay
panel
contains
five
relay
positions
.
In
lat-

er
modeis
an
additional
fuse
holder
(Fuse48)
and
the
EWS
II
(anti-theft)
transmitter/receiver
module
are
located
on
this

panel
.
See
Fig
.
3
.

The
panel
is
located
nextto
the
steering
column
under
the
driver's
side
dashboard
.
To
access
this
panel,
remove
the
pwer
dash
panel
on
driver's
side
.
See513
Interior
Trim
.

Then
remove
the
driver's
side
knee
bolster
.
Lower
the
relay
panel
by
gently
releasing
the
plastic
retainers
.
See
Fig
.
4
.

During
installation,
be
sure
the
retainer
tabs
are
engaged
in
the
relay
panel
.

Splice
Panel,
Left

3

¡ni

Fig
.
3
.
Auxiliary
relay
panel
under
left
side
of
dash
.

Fuse
48)
0013035

1
.



Comfort
relay
(where
ap-



4
.



Not
used

plicable)



5
.



Not
used

2
.
Crash
control
module



6
.



EWS
II
transmitter/receiv-

3
.



Park
ventilation
relay



er
module
(from
Jan
.
1995)

0013164

Fig
.
4
.



Auxiliary
relay
panel
under
left
sideof
dashboard
(arrow)
.

The
left
splice
panel
contains
four
relay
positions
and
an
ad-
ditional
fuse
holder
(Fuses
47
and
50)
.

To
access
the
left
side
electrical
splice
panel,
remove
the

left
side
dash
panel
and
knee
bolster,
as
described
earlier
.

The
panel
is
located
above
and
lo
the
left
of
the
clutch
pedal
.

See
Fig
.
5
.

Fig
.
5
.



Splice
panel
under
left
side
of
dash
.

SplicePanel,
Right

ir1!
1,
111lí~lll
.

'

ELECTRICAL
COMPONENT
LOCATIONS



610-3

0013091

1
.



Unloader
relay



4
.



Starter
immobilization
2
.



Wiper
relay



relay
(1994
only)
3
.
Wiper
motor
relay



F47
&
F50
Fuses47
and
50

The
right
splice
panel
contains
three
relay
positions
.
It
is
lo-

cated
under
the
right
side
of
the
dashboard
.

To
access
the
panel,
remove
theglove
compartment
as
de-
scribed
in
513
Interior
Trim
.
See
Fig
.
6
.

Fig
.
6
.



Splice
panel
under
right
side
of
dash
(arrow)
.
Glove
compart-
ment
and
right
side
vents
shown
removed
.

COMPONENT
LOCATIONS

On
the
following
pages
are
illustrations
and
photos
showing
the
location
of
major
electrical
components
in
E36
vehicles
.

NOTE-

-
Every
component
is
not
installed
in
everycar
.

"
Due
to
changes
in
production,
component
locations
may
vary
from
what
is
illustrated
.
Consult
your
BMW
dealer
for
the
latest
information
.

"
The
gear-position/neutral
safety
switch
ís
also
some-
times
referred
to
as
the
automatic
transmission
range
switch
.

"
The
EWS
11
system
is
also
sometimes
referred
to
as
the
Driveaway
Protection
System
or
the
electronic
im-
mobilization
system
.

"
All-Season
Traction
(AST)
is
also
sometimes
referred
to
as
ASC
or
ASC+T
.

COMPONENT
LOCATIONS

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