1996 BMW M3 wiring

640-4



HEATING
AND
AIR
CONDITIONING

Heater
box,
removing
and
installing

The
heater
box,
located
underneath
thecenter
of
the
dash-

board,
houses
theheater
core,
the
A/C
evaporator,
and
asso-

ciated
sensors
and
actuators
.
Removal
of
theheater
box

requires
that
the
A/C
refrigerant
be
discharged
.

CAUTION-

"
Removing
the
heater
box
requires
evacuating
the
AIC
system
.
DO
NOT
attempt
this
procedure
without
proper
tools
and
training
.

"
Any
person
who
services
a
motor
vehicle
air
con-

ditioner
must,
by
law,
be
properly
trained
and
cer-
tified,
and
use
approved
refrigerant
recycling
equipment
.
Technicians
must
complete
an
EPA-
approved
recycling
course
to
be
certified
UU12639

Fig
.
10
.
Heater
core
mounting
nuts
at
left
sideof
bulkhead
(arrow)
.

1
.
Drain
engine
coolant
.
See
170
Radiator
and
Cooling



wiper
assembly
shown
removed
for
clarity
.

System
.

2
.
Remove
complete
dashboard
.
See513
Interior
Trim
.

3
.
Remove
blower
motoras
described
earlier
.

4
.
Remove
nut
retaining
water
hose
flange
to
rear
bulk-
head
.
I'ush
flange
to
one
side
.
See
Fig
.
9
.

Fig
.
9
.



Nut
retaining
coolant
hose
flangeat
bulkhead
(arrow)
.

NOTE-

Clear
any
remaining
coolant
from
the
heater
core
by
blowing
compressed
air
finto
the
coolant
feed
hose
.

HEATER
AND
CONTROLS

0012638b

6
.
Cut
wire
tie
holding
wire
harness
to
heater
box
and
dis-

connect
cable
harness
connector
from
heater
box
.
See

Fig
.
11
.

0012647

Fig
.
11
.
Harness
connectors
(A)
and
cable
tie
(B)
at
heaterbox,
under
driver
side
dash
.

7
.
Followingmanufacturer's
instructions,
connect
ap-

proved
refrigerant
recovery/recycling/recharging
unitto

A/C
system
and
discharge
system
.

8
.
Unbolt
A/C
refrigerantlines
flange
from
engine
bay
bulkhead
.
See
Fig
.
12
.

9
.
On
models
with
rotary-knob
A/C
control
head
:
Discon-
5
.
Remove
nuts
from
heater
box
retaining
bracket
on
en-



nect
wiring
harness
connectors
to
A/C
control
module
gine
bulkhead
left
side
.
See
Fig
.
10
.
Repeat
procedure



in
center
console
and
remove
module
.
See
Fig
.
13
.
for
right
side
nuts
.

640-8



HEATING
AND
AIR
CONDITIONING

0012649

Fig
.
22
.
A/
C
control
head
faceplate
screwson
rotary
knob
version
(ar-
rows)
.
Once
screws
are
removed,
faceplate
must
be
un-
clipped
from
control
head
.

Fig
.
23
.
Push
control
panel
out
ofcenter
console
.

4
.
Remove
harness
connectors
.
Unfasten
heater
duct
control
flex-shaft
on
right
side
of
control
head
by
squeezing
retaining
tab
.
PA
shaftout
of
coupling
in
control
head
and
remove
head
.

5
.
Installation
is
reverseof
removal
.

HEATER
AND
CONTROLS

0012650

Heater
and
A/C
control
head,

removing
and
installing(digital-display)

1
.
Remove
Multi-Information
Display
(MID)
module
from

center
of
dash
.
See
620
Instruments
.

2
.
Reach
into
dash
through
MID
opening
and
push
A/C

control
head
outwards
.

3
.
Disconnect
harness
connector
and
remove
control

head
.

4
.
Installation
is
reverse
of
removal

Heater
andA/C
control
module,

removing
and
installing
(rotary-knob)

1
.
Remove
Multi-Information
Display
(MID)
module
from

center
of
dash
.
See
620
Instruments
.

2
.
Remove
center
console
.
See
513
Interior
Trim
.

3
.
Disconnect
wiring
harness
connectors
to
A/C
control

module
in
center
console
and
removemodule
.
See
Fig
.

24
.

0013007
Fig
.
24
.
A/
C
control
module
(A)
in
center
console
.
Arrows
point
to
electrical
harness
connectors
at
A/Cmodule
.

Heater
and
A/C
control
module,

removing
and
installing(digital-display)

TheA/C
control
module
for
cars
with
the
digital
display
is
mounted
on
the
back
of
the
control
head
.
See
Fig
.
25
.

1
.
Remove
control
head
as
described
earlier
and
place
onan
anti-static
mat
.

640-10



HEATING
AND
AIR
CONDITIONING

i

El
Radio

Antenna

Rear



.
,



si,-
Left
side



I
d

1
.
Rear
vents
2
.
Fresh
air
3
.
Face-level
vents
4
.
Recirculation
5
.
Footwell
vents
0013017

Fig
.
28
.
Location
oflate
production
air
distribution
motors
in
heater
box(shown
in
rear,
side
and
top
views)
.

Heater
andA/C
air
distribution
motor,

replacing
(rotary-knob)

1
.
Toaccess
left
side
motors
(dash
vent
mixing
or
recircu-

lation
flap),
remove
lower
dash
panel
and
knee
bolster

on
driver
side
.
See
513
Interior
Trim
.

2
.
To
access
right
side
motor
(fresh
air
flap),
remove
glove

compartment
.
See513
Interior
Trim
.

3
.
Each
motor
can
be
removed
after
its
electrical
wiring

harness
connector
has
been
removed
.
Squeeze
plastic

clip
to
release
motor
.
See
Fig
.
29
.

Fig
.
29
.
A/
C
air
distribution
motor
plastic
retaíning
clip
(arrow)
.
Re-
lease
clip
and
tilt
motor
out
of
housing
.

Rear
Window
Defogger

0011877

The
rear
window
defogger
switch
is
integrated
with
the
heating
andA/C
control
head
.

HEATER
AND
CONTROLS

Fig
.
30
.
Wiring
diagram
of
rear
window
defogger
and
radio
antenna
.

Rear
Window
Blower
(Convertible
Models)

A
blower
fan,
fitted
into
the
rear
seatback,
defogs
therear

window
.
It
will
only
operate
with
the
engine
nunning
and
the

top
raised
.
A
microswitch
behindthe
rear
seats
provides
the

signal
that
thetop
is
raised
.

To
access
the
blower
fan
motor,
it
is
necessary
to
remove

four
screwsfrom
the
center
seat
back
.
Remove
the
wiring
har-

ness
connector
and
motor
mounting
boits,
then
remove
motor

by
pulling
it
down
and
forward
.
See
Fig
.
31
.

ri

Suppressor
filter

1
0013005

Fig
.
31
.
Rear
window
blower
in
center
of
rear
seat
back
(arrow)
.

The
electric
rear
window
defogger
is
integrated
with
the
ra-

dio
antenna
.
See
Fig
.
30
.



y



/f



0013014

640-16



HEATING
AND
AIR
CONDITIONING

A/C
expansion
valve,

removing
and
installing

Fig
.
45
.
Control
module
carrier
retaining
screws
(arrows)
.

1
.
Following
manufacturers
instructions,
connectanap-

proved
refrigerant
recovery/recycling/recharging
unit
to

A/C
system
and
discharge
system
.

WARNING
-

Do
not
discharge%harge
the
WC
system
without
properequipmentand
training
.
Damage
to
the
vehi-

cle
and
personal
injury
may
result
.

2
.
Remove
glove
compartment
and
glove
compartment

support
frame
.
See513
Interior
Trim
.

3
.
Remove
right
side
footwell
vents
.

4
.
Remove
right
side
control
module
carrier
screws
and
tilt

carrier
down
.
See
Fig
.
46
.

5
.
Remove
expansion
valve
cover
.
See
Fig
.
46
.

Fig
.
46
.
Four
screws
retain
expansion
valve
cover
(arrows)
.

AIR
CONDITIONING

0012666
0012663

6
.
Remove
A/C
refrigerant
line
fiange
bolt(s)
from
expan-

sion
valve
.
Plug
lines
immediately
.
See
Fig
.
47
.

NOTE
-

If
necessary,
remove
air
plenum
grille
fromrear
of
en-

gine
compartment
as
described
earlier
in
Blower
mo-

tor,
removing
and
installing
.
Remove
wiring
hamess

cover
screws
and
then
remove
right
side
plenum
screws
.
Reaching
finto
the
plenum
chamber,
remove
AIC
fine
flange
bolt
to
allow
expansion
valve
room
for
removal
.

Fig
.
47
.
Refrigerant
line
fiange
mounting
boltat
expansion
valve(arrow)
.

7
.
Remove
screws
from
top
of
expansion
valve
and
re-

move
expansion
valve
from
evaporator
.
See
Fig
.
48
.

Fig
.
48
.
Expansion
valve
mountingscrews
(A)
.

0011667

650-2
RADIO

"
A
320-watt
Harmon-Kardon
ten
speaker
system,
including



RADIO
AND
SPEAKER
SERVICE
a
separate
high
power
multi-channel
audio
amplifier
and
two
sub-woofers
.
In
this
system,
thebass
and
volume
out-

puts
from
the
selected
audiosource
automatically
com-



Radio,
removing
and
installing

pensate
for
vehicle
speed,
making
constant
volume

adjustments
unnecessary
.
An
additional
feature
ofthis



CAUTION-
sound
system
is
the
ability
to
switch
from
normal
left-right



"
Before
beginning
work
on
the
radio
or
sound
stereo
into
Spatial
Enhancement
Mode,
which
produces
a



system,
verify
that
the
radio
is
an
original
equip-
fuller,
rounder
sound
.
See
Fig
.
3
.



ment
BMW
radio
and
that
thewiring
harness
has
not
been
modified
.
TheE36
radio
is
also
equipped
with
a
built-in
anti-theft
sys-

tem
.
lf
power
is
removed
from
the
radio
circuitry
by
removing

the
radio
electrical
connectors,
or
by
disconnecting
the
bat-
tery,
the
radio
is
rendered
inoperative
.
The
radio
is
not
perma-

nently
damaged,
and
proper
operation
can
be
restored
by

entering
the
radio
anti-theft
code
.

Fig
.
3
.
Ten
speaker
sound
system
.

RADIO
AND
SPEAKER
SERVICE

"
Servicing
of
aftermarket
sound
equipment
should
be
referredto
an
authorized
agent
of
the
equip-
ment's
manufacturer
.

"
Do
not
remove
radio
or
disconnect
the
batterywithout
first
obtaining
the
anti-theft
code
.

1.
Carefully
pry
open
small
square
covers
at
left
and
right

sides
of
radio
.

721-2



AIRBAG
SYSTEM
(SRS)

Fig
.
1
.



Airbag
system
components
.

AIRBAG
SENSORSAND
ELECTRONICS

CA
UTION-

"
If
an
airbag
is
activated,
the
following
compo-
nents
must
be
replaced
:
Airbag
with
contact
ring
;
-Pyrotechnic
seat
belt
tensioners
(if
fitted)
;
-SRS
Control
module
;
-Impact
sensors
;
All
airbags
which
did
not
deploy
.

"
Consult
your
BMW
dealer
for
parts
and
service
information
.

TheE36
airbag
system
consists
of
the
following
compo-

nents
:
crash
sensors
(in
earlycars,
through
1993),
an
elec-

tronic
control/monitoring
module
(with
integrated
crash

sensor
in
ZAE
systems),
an
indicator
light
in
the
instrument
panel,
and
inflatable
airbags
equipped
with
gas
generators
in

the
steering
wheel
and
in
the
passenger
side
of
the
instrument

panel
(ZAE
systems)
.

Some
1997
and
al¡
1998
carsalso
have
side-impact
airbags

in
the
front
doors
.

AIRBAG
SENSORS
AND
ELECTRONICS

1.
Crash
sensors
(through
1993)



wheel
2
.



SRS
control
module
in
front
of



5
.



Side-impact
airbags
(1997/98)
glove
compartment
(through



6
.
ZAE
control
module
under
rear
1993)



seat
(from
1994)
3
.



Passenger
side
airbag
unit
in



7
.
Side-impact
airbag
crash
sensors
dashboard
(ZAE
system)



in
door
silis
(1997/98)
4
.



Driver
side
airbag
unitin
steering



8
.



Knee
bolsters

In
addition
to
the
airbags,
the
vehicles
are
equipped
wíth

knee
bolsters
for
extra
protection
.

SRS
Warning
Light
and
Fault
Display

The
airbag
system
utilizes
a
self-diagnostic
control
module

to
detect
and
store
system
faults
.
If
a
fault
is
detected,
the

SRS
indicator
in
the
instrument
cluster
comes
on
and
stays

on
.

When
the
ignition
key
is
tumed
on,
the
indicator
light
will
illu-

minate
for
approximately
4-6
seconds
.
The
illuminated
light

indicates
the
self-testof
the
electronic
control/monitoring

module,
the
ignítors
and
crash-sensorcircuits,
and
the
system

wiring
.
The
airbag
system
should
be
inspected
byan
autho-

rized
BMW
dealer
if
the
indicator
light
does
not
come
on,
ifit

does
not
go
out
in
approximately
4-6
seconds
after
switching

onthe
ignition,
or
if
the
light
comes
on
during
driving
.
If
the

system
has
detected
a
fault,
the
light
will
come
on
and
stay
on
.

1
.
Disconnect
negative
(-)
cable
from
battery
and
cover

negative
terminal
with
insulating
material
.

CA
UTION-

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

2
.
Remove
driver
sideairbag
from
steering
wheel
.
See

Driver
side
airbag,
removing
and
installing
in
this

repair
group
.

3
.
With
wheels
facing
straight
ahead
and
steering
wheel

centered,
remove
steering
wheel
.
See320
Steering
and
Wheel
Alignment
.

4
.
Remove
contact
ring
cover
(flat
plastic
ring
containing

warning
text)
from
steering
wheel,
íf
applicable
.

5
.
Disconnect
ground
wire,
if
applicable

6
.
Lift
out
plastic
lock
from
steering
wheel,
if
applicable
.

See
Fig
.
2
.

0011903

Fig
.
2
.



Airbag
contact
ring
lock(arrow)
.
Pry
out
lock
and
remove
spríng
from
behind
lock
.
Some
airbag
steering
wheels
are
not
equipped
with
contact
ring
lock
.

WARNING
-

"
The
contact
ring
lock
holds
the
contact
ring
in
the
centered
position
.
Once
the
lock
is
removed,
the
contact
ring
is
free
to
rotate
.
Do
not
allow
the
con-

tact
ring
to
rotate
once
the
lock
is
removed
.

"
If
the
contact
ring
is
accidentally
rotated
outof
center,
turn
the
ring
either
fully
clockwise
orcoun-
terclockwise,
then
turn
in
the
opposite
direction
3
complete
revolutions
until
the
alignment
arrow
canbe
seen
through
the
lock
opening
.

AIRBAG
SYSTEM
(SRS)



721-
3

Airbagcontact
ring,
replacing



7
.
Remove
mounting
nutsor
screws
from
contact
ring
.

See
Fig
.
3
.
Disconnect
wire
lead(s)
andremove
contact

The
airbag
contact
ring
is
mounted
to
the
rear
of
the
steer-



ring
from
rear
of
steering
wheel
.

ing
wheel
and
is
made
up
of
a
wireribbon
that
cofs
and
un-

coils
as
the
steering
wheel
is
tumed
.
The
contact
ring
assures
continuous
electrical
contact
to
the
driver
side
airbag
unit
.

Fig
.
3
.



Airbag
contact
ring
mounting
fasteners(arrows)
.

8
.
Installation
is
reverse
ofremoval,noting
the
following
:

"
Coat
horn
slip
ring
(electrical
contact
ring)
with
CRC
®
copper
paste
before
installing
steering
wheel
.

"
Press
on
lower
lock
until
it
ís
fully
engaged
.

"
When
installing
contact
ringlock,
make
sure
lock

spring
engages
pins
on
lock
and
lock
cover
.

"
Special
instructions
apply
when
installing
airbag

equipped
steering
wheel
.
See320
Steering
and

Wheel
Alignment
.

Early
cars
(through
1993)
:

"
Route
wiring
lead
for
horn
through
squareopening
in

steering
wheel
.

"
When
installing
a
new
contact
ring
from
BMW,
remove

locking
screw
after
installing
the
contact
ringto
steer-

ing
wheel
.
See
Fig
.
4
.

"
Lock
contact
ring
mounting
fasteners
in
place
using

lacquer
paint
or
varnish
.

0011904

Fig
.
4
.



Airbag
contact
ring
locking
screw
(arrow),
as
installed
on
new

replacement
part
from
BMW
(early
production
cars)
.

AIRBAG
SENSORS
AND
ELECTRONICS

721-
6



AIRBAG
SYSTEM
(SRS)

5
.
Carefully
lift
airbag
unit
off
steering
wheel
and
discon-



6
.
Installation
is
reverse
of
removal
.
Tighten
right
side
nect
orange
harness
connector
from
rear
of
airbag
unit
.



screw
on
airbag
first
(as
viewedfrom
driver's
seat),

See
Fig
.
10
.



then
left
side
screw
.

NOTE-



NOTE-

In
some
models,
theairbag
electrical
connection
to
the



If
there
is
no
electrical
harness
connector
between
the
steering
wheel
isvia
aplug
in
back
of
the
airbag
unit
.



airbag
and
the
steering
wheel,
be
sure
to
fit
the
push
There
is
no
wire
harness
to
disconnect
.



in
electrical
plug
in
back
of
the
airbag
finto
the
proper
re-
ceptacle
in
the
steering
wheel
.

Fig
.
10
.
Driver
sideairbag
unit
harness
connector
(arrow)
.

AIRBAGS

WARNING
-

"
Store
the
removed
airbag
unit
with
the
horn
pad
facing
up
.
If
stored
facing
down,
accidental
de-
ployment
couldpropel
it
violently
into
the
air,
causing
injury
.

"
Once
an
airbag
is
removed,
the
car
must
not
be
driven
.

"
Do
not
connect
the
battery
with
the
airbag
dis-
connected
.
A
fault
code
will
be
stored,
setting
off
the
SRS
warning
light
.
Special
tools
are
needed
to
reset
the
fault
memory
.

"
Special
instructions
apply
when
installing
an
air-
bag
equipped
steering
wheel
.
See
320
Steering
and
Wheel
Alignment
.

"
Once
the
airbag
unit
is
installnd
and
all
other
ser-vice
procedureshave
been
completed,
start
the
engíne
and
check
that
the
SRS
warning
light
goes
out
.
If
the
warning
light
stays
on,
the
SRS
system
will
not
function
as
designed
.
Have
the
system
diagnosed
and
repaired
by
an
authorized
BMW
dealer
.

0013184

Tightening
Torque

"
Airbag
unitto
steering
wheel
........
8
Nm
(71
in-lb)

Passenger
side
airbag,

removing
and
installing

1
.
Disconnect
negative
(-)
cable
from
battery
and
cover
negative
terminal
with
insulating
material
.

2
.
Remove
glove
compartment
.
See
513
Interior
Trim
.

3
.
Lift
cover
from
topof
passenger
sideairbag
on
dash-
board
.
See
Fig
.
11
.

0013108
Fig
.
11
.
After
removing
glove
compartment,
lift
out
passenger
side
air-
bag
cover
.
Note
airbag
mounting
bolts
(A)
and
airbag
electri-
cal
connector
(B)
.

4
.
Remove
passenger
sideairbag
mounting
bolts
.
Dis-
connect
electrical
harness
connector
from
rear
of
air-
bag
unit
and
remove
airbag
.

5
.
Installation
is
reverse
of
removal
.
Make
sure
wiring
har-
ness
is
not
pínched
when
installing
airbag
unit
in
dash-board
.