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
To
access
the
rear
window
blower
relay,
remove
the
glove
compariment
.
See
Fig
.
32
.
Fig
.
32
.
Rear
window
blower
relay
located
in
frontof
glove
compart-
ment
(arrow)
.
AIR
CONDITIONING
Thissection
covers
removal
and
installation
of
air
condition-
ing
refrigerant
components
.
A/C
testing
and
diagnosis,
refrig-
erantdischarge,
evacuatíon
and
recharge
are
not
covered
here
.
The
subassemblies
and
lines
of
the
air
conditionerare
filled
with
either
refrigerant
R12
(1992
cars)
or
R-134a
(1993
and
later
cars)
.
The
major
components
of
the
A/Csystem
are
shown
in
Fig
.
33
.
A/CSystem
Warnings
and
Cautions
WARNING
-
"
Always
be
careful
that
refrigerant
does
not
come
in
contact
with
your
skin
.
Always
wearhand
andeye
protection
(gloves
and
goggles)
when
work-
ing
around
the
AIC
system
.
If
refrigerant
does
come
in
contact
with
your
skin
oreyes
:
-Do
not
rub
skin
oreyes
;
-Immediately
flush
skin
oreyes
withcool
water
for
15
minutes
;
-Rush
to
a
doctor
orhospital
;
-Do
not
attempt
to
treat
yourself
.
"
Work
in
a
wefl
ventilated
area
.
Avoid
breathing
re-
frigerant
vapors
.
Exposure
may
irrítate
eyes,
nose,
and
throat
.
Switch
on
exhaustlventilation
systems
when
working
on
the
refrigerant
system
.
"
Do
not
expose
any
component
of
the
AIC
system
to
high
temperatures
(Above
80°Cl176°F)or
open
flames
.
Excessive
heat
will
cause
a
pres-
sureincrease
whichcould
burst
the
system
.
HEATING
AND
AIR
CONDITIONING
640-
1
1
0013015
WARNING
-
"
Keep
refrigerant
away
from
open
llames
.
Poison-
ous
gas
will
be
produced
if
it
bums
.
Do
not
smoke
near
refrigerant
gases
for
the
same
reason
.
"
The
AICsystem
is
filled
with
refrigerant
gas
which
is
under
pressure
.
Pressurized
refrigerant
in
the
presenceof
oxygen
may
forma
combusti-
ble
mixture
.
Never
introduce
compressed
air
finto
any
refrigerant
container
(full
or
empty),
capped
off
AIC
component,
or
piece
of
service
equip-
ment
.
"
Refrígerant
gases
are
heavier
than
air,
displace
oxygen
and
may
cause
suffocation
in
areas
of
poor
círculation,
for
example
under
a
car
.
Switch
on
exhaustlventilation
systems
when
working
on
the
refrigerant
system
.
"
State
and
local
governments
may
have
additional
requirements
regarding
air
conditioning
servic-
ing
.
Alwayscomply
with
state
and
local
laws
.
"
Electric
welding
near
refrigerant
hoses
causes
R-134a
to
decompose
.
Discharge
system
before
welding
.
CA
UTION
-
-As
of
January
1,
1992,
any
person
who
services
a
motor
vehicle
air
conditioner
must,
by
law,
be
properly
trained
and
certified,
and
use
approved
refrigerant
recycling
equipment
.
Technicians
must
complete
an
EPA-approved
recycling
course
to
be
certified
.
"
It
is
recommended
that
al¡
system
refrigerant
AIC
refrigerant
be
left
to
an
authorized
BMW
dealer
or
other
qualified
AIC
service
facility
.
"
Do
not
top
off
a
partially
charged
refrigerant
sys-
tem
.
Dischargesystem,evacuate
and
then
re-
charge
system
.
"
R-134a
and
R-12
refrigerants
and
refrigerant
oils
and
system
components,
including
hoses
and
sealing
O-rings,
are
NOT
compatible
.
Compo-
nent
damage
andlor
system
contamination
will
result
.
"
The
mixture
of
refrigerant
oil
(PAG
oil)
and
refrig-
erant
R-134a
attacks
some
metals
and
alloys
(for
example,copper)
and
breaks
down
certain
hose
materials
.
Use
only
hoses
and
lines
that
are
iden-
tified
with
a
green
mark
(stripe)
or
the
lettering
R-
134a"
.
"
Immediately
plug
open
connections
on
AIC
com-
ponents
to
prevent
dirt
and
moisture
contamina-
tion
.
"
Do
not
steam
clean
condensers
or
evaporators
.
Use
only
cold
water
or
compressed
air
.
AIR
CONDITIONING
