1995 BMW M3 head

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
.

Fig
.
12
.
Mounting
bolt
for
A/C
refrigerant
line
flange
(arrow)
.

001Suu7

Fig
.
13
.
A/
C
control
module
(A)
behind
center
console
.
Arrows
pointto
electrical
harness
connectors
to
be
disconnected
.

CAUTION
-

Replace
heater
and
AIC
flange
O-rings
and
tight-

en
fasteners
to
specified
torques
.

0012644

HEATING
AND
AIR
CONDITIONING



640-5

Fig
.
14
.
Heating
and
ventilation
ducts
on
left
side
of
heater
box
(arrows)
.
Right
side
ducts
are
similar
.

Fig
.
15
.
Heater
box
retaining
bracket
in
center
console
(arrow)
.

0012645

10
.
Unclip
andremove
heating
and
ventilation
ducts
on



Tightening
Torques

sides
of
heater
box
.
See
Fig
.
14
.



"
A/C
refrigerant
lines
flange

to
bulkhead
..............
.
..
..
.
3
.5
Nm
(31
in-lb)

11
.
Remove
heater
box
retaining
bracket
on
center
tunnel



"
Water
hose
flange
to
bulkhead

and
remove
heater
box
.
See
Fig
.
15
.



(M6
nut)
................
.
...
..
3
.5
Nm
(31
in-lb)

"
Heater
box
retaining
bracket

12
.
Installation
is
reverse
of
removal
.
Evacuate
and
re-



to
tunnel
................
.
..
..
.
4
.5
Nm
(40
in-lb)

charge
A/C
system
using
specialized
equipment
.
Fill

and
bleed
cooling
system
.
See
170
Radiator
and

Cooling
System
.

HEATER
AND
CONTROLS

10
.
Pul¡
heater
core
up
and
backward,
away
from
heater
box
.
If
necessary,
remove
left
and
right
reinforcing
bracket
bolts
.
See
Fig
.
20
.

CAUTION-

Replace
coolant
flange
O-rings
and
tighten
fas-
teners
to
specified
torques
.

Tightening
Torques

1
.
Remove
center
console
.
See
513
Interior
trim
.

0012660

Fig
.
20
.
PA
heater
core
upand
towardback
of
car
.
Lower
mounting
bolts
for
steering
column
brace
and
glove
compartment
sup-
port
frame
may
have
to
be
removed
(arrows)
.

11
.
Installation
is
reverse
of
removal
.
Fill
and
bleed
cooling

system
.
See
170
Radiator
and
Cooling
System
.

"
Coolant
flange
to
heater
core
.
..
....
3
Nm
(27
in-lb)



Heater
andA/C
Control
Head

Heatercore
temperature
sensor,
replacing

The
automatic
heating
and
air
conditioning
systemuses

severa¡
sensors
to
control
interior
air
temperature
.
Use
the
fol-

lowing
procedure
and
the
data
in
Table
b
to
pinpoint
problems

with
theheater
core
sensors
.

2
.
Remove
Multi-Information
Display
(MID)
module
.
See

6201nstruments
.

HEATING
AND
AIR
CONDITIONING



640-7

0012648

Fig
.
21
.
Remove
heatercore
temperaturesensors
in
direction
shown
(arrow)
.

Table
b
.
Heater
CoreTemperatureSensor
Test

Values

Test
temperature



Resistance

4°F
(-20°C)



84
.39
-
109
.61
k
ohms

14
°
F
(-10°C)



48
.58
-
62
.09
k
ohms

32°F
(0°C)



28
.89
-
36
.40
k
ohms

68°F
(20°C)



11
.13
-
13
.83
k
ohms

140°F
(60°C)



2
.19
-
2
.78
k
ohms

212°F
(100°C)



0
.58
-
0
.77
k
ohms

Two
types
of
heater
and
aír
conditioning
control
heads
viere
installed
in
E36
cars
.
Early
models
have
control
heads
with
four
rotary
knobs
and
a
separate
control
module
.
A
flexible

shaft,
clipped
to
the
right
sideof
the
control
head,
controls
the
heater
flaps
.

Later
model
E36
cars,
starting
in
approximately
mid-1995,

have
digital
display
control
heads
with
buttons
.
The
A/C
con-
trol
module
is
integrated
with
the
digital
control
head
.

Heater
and
A/C
control
head,

removing
and
installing
(rotary-knob)

3
.
Pul¡
temperature
sensors
from
heater
box
and
discon-



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

nect
harness
connectors
.
See
Fig
.
21
.



center
of
dash
.
See
620
Instruments
.

4
.
Installation
is
reverse
of
removal
.



2
.
Pul¡
off
outer
rotary
knobs
from
A/C
control
head
.
Re-

move
two
screwsonknob
bezels
.
Remove
control
pan-

el
face
plate
by
prying
it
off
control
head
gently
.
See
Fig
.

22
.

3
.
Carefully
push
control
head
back
into
dash
and
down-

ward
through
MID
opening
.
See
Fig
.
23
.

HEATER
AND
CONTROLS

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
.

Sensor

fan

Fig
.
25
.
Digital
display
A/C
control
head
components
.

2
.
Unscrew
left
and
right
screws
retaining
control
head
to
control
module
.
Press
retaining
clips
and
release
front
plate
from
control
head
.
Remove
A/C
control
module
from
control
head
housing
.

Sensor
fan
for
interior
temperature,

repiacing

A
small
electricfan,installed
in
the
A/C
control
head,
draws
cabin
air
past
the
climate
control
temperature
sensor
.

1.
Remove
A/C
control
head
as
described
earlier
.

2
.
Rotary-knob
control
head
:
Disconnect
electrical
con-
nector
from
top
of
control
head
housing
.
Pry
open
plas-

tic
housing
and
remove
sensor
fan
.
See
Fig
.
26
.

0013181

Fig
.
26
.
Sensor
fan
(A)
and
harness
(B)
in
back
of
A/C
control
head
(rotary-knob
control
head
shown)
.

3
.
Digital
display
models
:
Disconnect
electrical
harness

connector
from
control
head
housing
.
Remove
screws

holding
sensor
fan
to
bottom
of
control
moduleand
re-
move
.
Refer
to
Fig
.
25
.

4
.
Installation
is
reverse
of
removal
.

HEATING
AND
AIR
CONDITIONING



640-
9

Heater
and
A/C
Air
Distribution
Motors

The
recirculation,
fresh
air
and
othervent-duct
flaps
are
controlled
electrically
via
a
series
of
air
distribution
actuating
motors
.
Cars
with
the
rotary-knob
control
head
use
three
elec-
tromechanical
motors,
each
held
in
place
via
a
small
plastic
clip
.
See
Fig
.
27
.

Rightside
of
heater
box
l

Fig
.
27
.
Location
of
early
production
air
distribution
motors
(arrows)
.

Later
systems
(with
the
digital
display
control
head)
use
five
distribution
motors,
four
of
which
are
digítally
controlled
.
See
Fig
.
28
.

HEATER
AND
CONTROLS

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

Fig
.
42
.
Upper
A/C
condensermounting
bolts
(arrows)
.

8
.
Before
recharging,
evacuate
system
for
at
least
30
min
.
Recharge
system
following
equipment
manufacturer's
instructions
.
See
Table
d
.
A/C
System
Refrigerant

Capacities
.

A/C
receiver/drier,
replacing

The
A/C
receiver/drier
is
mounted
in
the
front
right
cornee
of
the
engine
compartment
behind
the
headlight
assembly
.

CAUTION-

The
receiver/drier
must
be
replaced
when
-There
is
dirt
in
the
AIC
system
-The
compressor
has
seized
or
has
been
re-
placed
for
any
reason
-The
condenser
or
evaporator
are
replaced
for
any
reason
-The
AIC
system
is
leaking
and
there
is
no
more
refrigerant
-The
AIC
system
was
open
for
24
hours
or
more
.

1
.
Following
manufacturer's
instructions,
connectan
ap-

proved
refrigerant
recovery/recycling/recharging
unit
to

A/C
system
and
discharge
system
.

2
.
Remove
right
headlight
assembly
.
See
630
Exterior
Lighting
.

CAUTION-
3
.
Disconnect
A/C
electrical
harness
connectors
.
See
Fig
.



Always
replaceO-rings
when
reconnecting
refrig-
43
.



erant
lines
.

4
.
Remove
refrigerant
pressure
lines
from
receiver/drier
.

Plug
lines
immediately
.

5
.
Remove
receiver/drier
mounting
bolts
.

0013182

6
.
Remove
underbody
splash
shield
on
passenger
side
.

See
Fig
.
44
.

7
.
Remove
passenger
side
brake
cooling
duct
.
Discon-

nect
outside
temperature
sensor
harness,
if
applicable
.

HEATING
AND
AIR
CONDITIONING



640-15

0012669

Fig
.
43
.
A/
C
receiver/drier
electrical
harness
connectors
(A),
pressure
line
retaining
bolts
(B),
andmounting
bolts
(C)
.

0012668
Fig
.
44
.
Passenger
sidesplash
shield
retaining
screws
(arrows)
.

8
.
Push
receiver/drier
down
andremove
from
underneath
car
.
Make
sure
that
receiver/drier
is
clear
of
any
electri-
cal
harnesses
.

9
.
Installation
is
reverse
of
removal
.

10
.
Before
recharging,
evacuate
system
for
at
least
30
min
.

Recharge
system
following
equipment
manufacturer's

instructions
.
See
Table
d
.
A/C
System
Refrigerant

Capacities
.

AIR
CONDITIONING

721
Airbag
System
(SRS)

Airbag
Systems
.......
.
...
.
.
.
.
.
....
.
.
.
.
721-1

AIRBAG
SENSORS
AND
ELECTRONICS
721-2

SRS
Warning
Light
and
Fault
Display
.
.
.
.
.
..
721-2

Airbagcontact
ring,
replacing
........
.
.
.
.
.
721-3

Airbag
crash
sensor,replacing
..
.
....
.
...
.
721-4

ZAE
control
module,
replacing
.
.
.
.........
721-5

GENERAL

This
repair
group
covers
only
removal
and
installation
of
air-
bag
components
.
Airbag
system
repair
and
fault
diagnosis
is
not
covered
here
.
Diagnostics,
component
testing,
and
airbag
system
repair
should
be
carried
out
by
trained
BMW
service
technicians
.

NOTE-

Special
test
equipment
is
required
to
retrieve
SRS
fault
codes,
diagnose
system
faults,
and
resetltum
off
the
SRS
indicator
light
.
The
SRS
indicator
light
will
remain
on
until
any
problem
has
been
corrected
and
the
fault
memory
has
been
cleared
.

When
servicing
cars
equipped
with
SRS,
the
precautions

on
this
page
mustbeobserved
to
prevent
personal
injury
.

Airbag
Systems

The
airbag
system
installed
on
E36
cars
through
the
1993
model
year
consisted
of
a
single
airbag
in
the
steering
wheel
.
This
systemcan
be
identified
by
the
orange
crash
sensors
lo-
cated
on
the
front
wheel
wells
and
the
absence
of
a
passenger
side
airbag
.

The
ZAE
airbag
system,
starting
in
model
year
1994
(pro-
duction
date9/93
and
later),
provides
both
a
driver
side
and
a
passenger
sideairbag
.
On
ZAE
vehicles,
the
crash
sensorsare
integrated
into
the
airbag
control
module,
located
under
thecenter
of
the
rear
seat
.
The
ZAE
control
module
triggers

deployment
of
the
airbags
When
it
sensos
the
vehicle
deceler-
ating
at
a
rate
equivalent
to
a
head-on
collisionof
at
least
13
mph
(18
km/h)
.

In
some
1997
4-door
models
and
all
1998
models,
side-impact
airbags
were
installed
in
the
front
doors
.
The
airbag
units
are

mounted
behindthe
door
trim
panels
.
Caution
mustbeused

when
working
on
vehicle
systems
in
the
proximity
of
air
bags,
such
as
the
steering
column,
the
dashboard,
or
the
doors
.

AIRBAG
SYSTEM
(SRS)



721-1

GENERAL
.
.
.
.
.
.
.
.
.
.
.......
.
......
.
.
.
.
721-1



Front
side-impact
airbag
crash
sensor,
removing
and
installing
....
.
.....
.
.....
.
721-5

AIRBAGS



..............
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
721-5

Driver
side
airbag,
removing
and
installing
.
.
.
721-5

Passenger
side
airbag,

removing
and
installing
..............
.
.
.721-6

Front
side-impact
airbag,
removing
and
installing
.
.
.
.
.
.
.
.
.
.
......
.721-7

WARNING
-

"
Airbag(s)
are
inflated
byan
explosive
device
.
Handled
improperly
or
without
adequate
safe-
guards,
the
System
can
be
very
dangerous
.
Spe-
cial
precautions
must
be
observed
prior
to
any
work
ator
near
the
driverside
airbag,
the
passen-
ger
side
airbag
(where
applicable)
or
the
side-im-
pact
airbags
(where
applicable)
.

"
The
airbag
is
a
vehicle
safety
system
.
Serious
in-
jury
may
result
if
System
service
is
attempted
by
persons
unfamiliar
with
the
BMW
SRS
and
its
ap-
proved
service
procedures
.
BMW
advises
that
all
inspection
and
service
be
performed
by
an
autho-
rized
BMW
dealer
.

"
Always
disconnect
the
battery
and
cover
the
neg-
ative
()
battery
terminal
with
an
insulator
before
startingdiagnostic,
troubleshooting
or
service
worknot
associated
with
SRS,
and
before
doing
any
welding
on
the
car
.

"
If
an
airbag
has
been
activated
due
to
an
acci-dent,
BMW
specifies
that
SRS
components
be
replaced
.
For
more
information
on
post-collision
SRS
service,
see
an
authorized
BMW
dealer
.

"
Do
not
allow
the
airbag
unit
to
come
in
contact
with
cleaning
solutions
orgrease
.
Never
subject
an
airbag
unit
to
temperatures
aboye
212°F
(100°C)
.
When
reconnecting
the
battery,
no
per-
son
should
be
inside
the
vehicle
.

"
Always
place
an
airbag
unitthat
has
been
re-
moved
from
its
packaging
with
the
padded
sidefacing
upward
.
Do
not
leave
an
airbag
unlt
unat-
tended
.

"
!f
the
airbag
unit
or
airbag
control
modulehas
been
dropped
froma
height
of
!
1
2
meter
(1
Y2
ft.)
ormore,
theairbag
unit
should
not
be
installed
.

Aírbag
system
components
are
shown
in
Fig
.
1.

GENERAL