1994 BMW 325i airconditioning system

NOTE
-

Sometimes
the
color
of
en
installed
wire
may
be
differ-
ent
than
the
one
on
the
wiring
diagram
.
Don't
be
con-
cerned
.
Just
be
sure
lo
confirm
that
the
wire
connects
lo
the
proper
terminals
.

Wire
color
codes

"
BLU
.........
.
..
..
...
.
.................
Blue

"
BRN
....:....
.
..
..
...
..
...............
Brown

"
YEL
.........
.
..
..
...................
.Yellow

"
GRN
.........
.
..
..
...
.
................
creen

"
G
RY
.......
.
.
.
..
..
.....................
G
ray

"
ORG
.........
.
..
..
...
.
..............
.Orange

"
RED
......
...
.
.
..
.....................
.Red

"
BLK
.........
.
..
..
...
.
................
Black

"
VIO
..........
.
..
...
..
..
.......
.
.......
Violet

"
WHT
.........
.
.
....
.
...
:..............
White

Table
a
.
Terminal
and
Circuit
Numbers

Number



1
Circuít
description

1



j
Low
voltage
switched
terminal
of
coi¡

4



1
High
voltage
center
termina¡
of
coi¡

+x



Originates
atignition
switch
.
Supplies
powerwhen
the
ignition
switch
is
in
the
PARK,
RUN,
or
START
position

15



Originates
atignition
switch
.
Supplies
powerwhen
ignition
switch
is
in
RUN
or
START
position

30



Battery
positive
(+)
voltage
.
Supplies
power
whenever
battery
is
connected
.
(Not
dependent
on
ignition
switch
position,
unfused)

31



1
Ground,
battery
negative
(-)
terminal

50



Supplies
power
from
battery
to
starter
solenoid
when
ignition
switch
isin
START
position
only

+54



Originates
atignition
switch
.
Supplies
power
when
ignition
switch
isin
the
RUN
position
only

85



1
Ground
side
(-)
ofrelay
coil

86



1
Power-in
side
(+)
ofrelay
coil

87



1
Relay
actuatedcontact

D



Alternator
warning
light
and
field
energizing
circuit

ELECTRICAL
SYSTEM-GENERAL
600-
3

Additional
abbreviations
shown
in
the
wiring
diagrams
are

given
below
.

Abbreviations

"
ABS
........
.
...
.
...
.
..........
antilock
brakes

"
A/C
........
.
...
..
..
.
.........
.airconditioning

"
AST/ASC+T
.......
...
.
.
.......
al¡
season
traction

"
CONV
.......
.
.
...
.................
convertible

"
DME
........
.
.
...
.......
digital
motor
electronics

"
ECM



.......
.
...
..
..
.
..
electronic
control
module

"
EWS/EWS
II
......
...
.
.
coded
driveaway
protection

"
SRS
........
.
supplemental
restraint
system-airbag

"
TCM
........
.
..
....
.
transmission
control
module

"
ZKE
(94-98
models)
..
..
.
...
central
body
electronics

"
ZVM
(92-93
models)
...
.
.
..
.
.......
central
locking

ELECTRICAL
TROUBLESHOOTING

Most
terminals
are
identified
by
numbers
on
the
compo-

nents
and
harness
connectors
.
The
terminal
numbers
for
ma-



Four
things
are
required
for
current
toflow
in
any
electrical

jor
electrical
connections
are
shown
in
the
diagrams
.
Though



circuit
:
a
voltagesource,
wires
or
connections
to
transport
the

many
terminal
numbers
appear
only
once,
severa¡other
num-



voltage,
a
load
or
device
that
uses
the
electricity,
and
a
con-
bers
appear
in
numerous
places
throughout
the
electrical
sys-



nection
to
ground
.
Most
problemscanbefound
using
a
digital

tem
and
identify
certain
types
ofcircuits
.
Some
of
the
most



multimeter
(volt/ohm/amp
meter)to
check
for
voltage
supply,

common
circuit
numbers
are
listed
below
in
Table
a
.



for
breaks
in
the
wiring
(infinite
resistance/no
continuity),
orfor

a
path
to
ground
that
completesthe
circuit
.

Electric
current
is
logical
in
its
flow,
always
moving
from
the

voltage
sourcetoward
ground
.
Electricalfaults
can
usually
be

located
through
a
process
of
elimination
.
When
troubleshoot-

ing
a
complex
circuit,
separate
the
circuit
into
smaller
parts
.

The
general
testsoutlined
below
may
be
helpful
in
finding

electrical
problems
.
The
information
is
most
helpful
when

used
with
the
wiring
diagrams
.

Be
sure
to
analyze
the
problem
.
Use
the
wiring
diagrams
to

determine
the
most
likely
cause
.
Getan
understanding
of
how

the
circuit
works
by
following
the
circuit
from
groundback
to

the
power
source
.

When
making
test
connections
at
connectors
andcompo-

nents,
use
care
to
avoidspreading
or
damaging
the
connec-

tors
or
terminals
.
Some
tests
may
require
jumper
wires
to

bypass
components
or
connections
in
the
wiring
harness
.

When
connecting
jumper
wires,
use
bladeconnectors
at
the

wire
ends
that
match
the
size
of
the
terminal
being
tested
.
The

small
interna¡
contacts
are
easily
spread
apart,
and
this
can

cause
intermittent
or
faultyconnections
that
can
leadto
more

problems
.

ELECTRICAL
TROUBLESHOOTING

640-6



HEATING
AND
AIRCONDITIONING

Heater
core,replacing

1.
Drain
engíne
coolant
.
See170
Radiator
and
Cooling

System
.

WARNING
-

Allow
the
cooling
system
to
cool
before
opening
or
drainíng
the
cooling
system
.

2
.
Remove
center
console
.
See
513
Interior
Trim
.

3
.
Remove
Multi-Information
Display
(MID)
module
.
See

620
Instruments
.

4
.
Remove
lower
dash
panel
and
knee
bolster
on
driver

side
.
See
513
Interior
Trim
.

Fig
.
17
.
Wire
harness
retaining
clips
and
wire
ties
at
heater
box
cover
5
.
Working
under
driver
side
of
dash,
remove
coolant



(arrows)
.
flange
from
heater
core
.
See
Fig
.
16
.

0012651

Fig
.
16
.
Bolts
at
3-way
coolant
flange
under
driver's
side
of
dash
(ar-
rows)
.

NOTE-

Residual
coolant
in
heater
core
will
spill
.
Protect
thecarpet
.

6
.
Working
at
front
of
driveshaft
tunnel,
unclip
wire
har-

nesses
and
move
to
one
side
in
front
of
heater
box
.
See
Fig
.
17
.

7
.
Remove
heatercore
temperature
sensorsas
described

later
in
this
repair
group
.

8
.
Remove
front
heater
box
cover
.
See
Fig
.
18
.

9
.
On
right
side
of
heater
box,
unclip
heater
air
duct
actu-
ating
lever
.
Remove
cross-rod
(with
flaps)
from
frontof
heater
core
.
See
Fig
.
19
.

HEATER
AND
CONTROLS

0012662

Fig
.
18
.
Screws
retaining
front
heater
box
cover
(shown
removed)
to
heater
box
(arrows)
.

0012661
Fig
.
19
.
Pry
heater
flap
actuating
lever
in
direction
A
.
Pull
offair
flap
cross-rod
in
direction
B
.

BLOWER
RELAY

77720

b
GFN/=RN
6
GF
OFF



N/RED
1



,~7
BL~K
2
11
GEN
3



2
BLU
4



3
G~RN/BRN

BLOWERBWITCH

OFF

CLIMATE
OFF

HOTAT



HOTINRUN



HOTINRUN



HOTAT



HOT
AT
HOTATALLTIMEB--



ALLTIMES



OR
START



ORSTART



ALL
TIMES



ALLTIMES

.1
19
VIOIGRY

GRN/YEL

8
RED/YEL

Air
Conditioning
&
Heating

1995
318ti

GRYIRED
INTERIOR
LIGHTS
SYSTEM

ELECTRICAL
WIRING
DIAGRAMS
ELE-135
AIRCONDITIONING
COMPRESSOR

REDIGRN
B
BLU
2
REDIGRN
B

GRNIBLU

BLKIGRY



j
(NOTUBE
D)
D)
HIGH
SPEEO
RELAY

NORMAL
SPEED
RELAY

1)ABOVE99
DEGC



AUXILIARY
2)ABOVE
91



FAN
MOTORDEGC



I
BLK

2
BEN
1

BLK/GRN
2

TEMPERATURE
SWITCH

87847

BLOWER
RELAY

6
GRN/BRN

.1
)2
GRNIBRN

B
CONTROL
SWITCH
GRY/RED

4
BRN



"BRN
+G202

RECIRC

RRDEFOG

INTEGRATEDHEATINGANDCLIMATECONTROL
MODULE

HOTAT



HOTINRUN



HOT
IN
RUN



HOTAT



HOT
AT
HOTATALLTIMES_



ALLTIMES



OR
START
_
__



_



ORSTART



ALLTIMES



ALLTIMES
r



71GNIT'ON



r



_
FU
_
SE



FUSE



FUSE



FUSE



FUSE



-
FRONT
POWER
I



S
WITCH



l
Box
I



I



I
20



23



18



39



41
BOXOFF



START



L
--_-
--5A-__
1
.5
=_--_
3
-_J
I



II



ACC
"



RUN



I

RED/YEL

EVAPORATOR
TEMPERATURE
SENSOR

Air
Conditioning
&
Heating

1997
318ti

BR=
'I
G201

,10
GRY/YEL

1
BRN

2
BRN
CLIMATE
CONTROL
S
WITCH
ILLUMINATION

ELECTRICAL
WIRING
DIAGRAMS
ELE-137

GRY/RED

DEFOGGER
SYSTEM

SOLID
S7A7E

WATER
FRESHAIR
TEMPERATURE
VALVE
COMPRESSORCONTROL
RECIRCULATIONMOTOR
WHEELSWITCH



RELAY



COMPRESSOR

BLU/BLK

BLKIGR

AIRCONDITIONING

BLKIBLU

_BLU
BRN

NORMALSPEEDRELAY

HIGH
SPEEDRELAY

1IABOVE88
DEGC



AUXILIARY
2)ABOVE80



FAN
MOTOR
DEG
C
BLK/GRN
3

+
.=N

1
L
----
'
+100



ABOVE
BLK
-
GRY


24



18BAR

BELOW
21
BAR

TEMPERATURE
SWITC

BELOW
15
BAR
ABOVE
2
.6
BAR
BELOW
ABOVE
1
.5
30BAR
BAR
PRESSURE
S
W
ITCH

BLK/
REDI
II
BB-K/
-
GRN
GRY
1



I
BlK/G
RV



85



I



I
VIO/G
RV



69



I



I
"
-LK/BLU
36,
I



I
L__I
ENGINE
CONTROL
MODULE

TRANSMISSION
CONTROL
MODULE