1977 DATSUN PICK-UP air condition

Air

Conditioning

COMPRESSOR

DIAGNOSES

I
COMPRESSOR

TROUBLE

Turn
the

compressor
dutch
wheel

by
hand

I

I

If

OK
j

Will
not
turn

Apply
12V
direct

current
to

compressor
clutch

Then
check
clutch

engagement

I

j

If
OK
I

Internal

problem
in

compressor
cylinder

Repair
or

replace
compressor

Check

voltage
oflead
wire

for

compressor
on

cooler
cable

I

I

If
OK
I
Clutch
does
not

engage

I

Clutch
is

damaged

Repair
or

replace
dutch

assembly

No

voltage

I

Internal

problem
in

compressor

Repair
or

replace

compressor
Check
or

repair
wiring
system
for

compressor

clutch

AC
22

Air

Conditioning

NOISE
DIAGNOSES

NOISY

I

I

I
Set
fan

switch
on

2

Change
the

engine
rpm

frequently

Detect

the
source
of

noise

I

From

engine
compartment
From
cabin

Cooling
unit

j

Check
the

resonant
sound
when
the

engine
rpm
is

changed

I

I

No

resonant
sound

Compressor
itself
makes
noise
j

Blower
motor

makes
noise

Replace
or

repair
blower

Resonant

sound

Repeat
compressor
clutch
ON
and

OFF

This

checking
can
be

performed
by
changing

engine
rpm
while

fan
switch
is

set
at

ON
Retighten
compressor
bracket
bolt

If

piping
is

resonating
add

clip

Noisy
only
when
clutch
is

engaged
Noisy
when

clutch
is
not

engaged

I

Check
drive
belt
for

slackness

Check
for
loose

compressor
mounting
bolts

I

I
Remove

compressor
belt
then
turn

compressor

pulley

by
hand
If
noise
is
heard

repair
com

pressor
clutch

If

OK

If
loose

Compressor
itself
makes
noise

Repair
or

replace
compressor
Retighten
or

adjust

Nl1

Air

Conditioning

BLOWER
MOTOR
DIAGNOSES

Blower
motor

inoperative

Check
fuse

In
fuse
block

15A
W

Single
fuse
15A
at

cooling
unit

I

j

If
OK

Check
the

continuity
and

fitting
of
fan
switch

I

I

If
OK

I

I

Connect
fan
switch
to

wiring
harness

2

Turn
the

ignition
switch
ON
IG

3
Set
fan
switch
at
ON
1
2
or
3

position

Check
the

voltage
for
blower
motor

Blue
lead
wire
is

poweI
source

Blue
wire

with
white

stripe
is

for

grounding

I

I
Voltage

I

I

Check
the

continuity
and

fitting
of
resistance
on

cooling
unit

I

I
If
OK
If

damaged

I
I

Replace
blower
motor
Replace
resistance

AC

24
mown
fuse

Replace
fuse

j

If

damaged

I

I

Replace
fan
switch

No

voltage

Replace
main
relay

Air

Conditioning

REMOVAL
AND
INSTALLATION

COMPRESSOR

REMOVAL

INSTALLATION

IDLER
PULLEY

FAN
BELT

TENSION
ADJUSTMENT

REMOVAL
AND
INSTALLATION

INSPECTION

COOLING
UNIT

REMOVAL
AND
INSTALLATION

DISASSEMBLY
AND
ASSEMBLY

INSPECTION

RECEIVER
DRYER
AND
PIPING

COMPRESSOR

REMOVAL

I
Remove

battery

2

Disconnect

compressor
lead
wire

at
connector

3
Loosen
idler

pulley
lock

nut
then

adjusting
bolt
Remove

compressor

drive
belt

from

compressor
pulley

AC477

Fig
AC
28

Removing
drive
belt

4

Discharge
system
Refer
to
Dis

charging
System
under
General
Service

section
CONTENTS

AC
25

AC25

AC26

AC
27

AC
27

AC27

AC
27

AC27

AC
27

AC
2B

AC
29

AC
29
REMOVAL

AND
INSTALLATION

INSPECTION

WIRING

HARNESS
AND

COMPONENTS

WIRING
DIAGRAM

MAINTENANCE

MAIN
RELAY

COMPRESSOR

RELAY

FAN
SWITCH

RESISTOR
FOR
FAN
SWITCH

THERMO
SWITCH

F
I

C
D
SOLENOID
VALVE
AC29

AC29

AC30

AC30

AC31

AC31

AC31

AC31

AC32

AC32

AC
32

5
Remove
flexible
hose

fixing
plate

and
disconnect
low
and

high
pressure

flexible
hoses
from

compressor

Notes

a
Use
two

wrenches
when
disconnect

ing
pipe

joints

b

Plug
flexible
hose
and

compressor

joint
openings
immediately
after

disconnection
to

prevent
entry
of

dust
moisture
laden
air
etc

Fig
AC
29

Disconnecting
ftexible

hoses

from
compressor

6
Remove

bolts

securing
fuel
tube

to

compressor
attachment

AC
25
Y
1

L

AC744

7
Remove
four
bolts

securing
com

pressor
to
its
bracket

Compressor
and

attachment

can
now
be
detached
as
an

assembly

Notes

a
There
are
a

total
of
four
bolts
two

on

upper
side
of
bracket
and
two

on
lower
side
of

compreSsor

Loosen

upper
bolts
and
remove

lower
bolts
When

removing
upper

bolts

securely
hold

compressor

with
one
hand

b
When

installing
temporarily
tighten

upper
bolts
then

tighten
lower

bolts

2

R

C7

c

L

PJJ

I

8

INSTALLATION

a
c
J

l
i
rp

To
install

compressor
reverse
the

order
of
removal
Observe
the

follow

ing
nhlJo
e
trorf
1001

vom
R

i
n3

Wheliqli
liiAniitg

fiil
l
in

pt
l

witlil
tiiel
sam
efuouiitITof

b11
1fasitlult

used

previously
v
d
rnl

2

Oil

capacity
new

compressor

O
910
1

owt
llllt
blj
f
H
w
s
013
5

rlT
s

0
111
boc

19
bB1rllo

bi2

qqll
no

e

l
bffik
kuanM
mpdi

x
of

Jli
oln

L
il
m
1IlffiiOrb

fler
ot
oldm

F
n

Cheo

f
undeF
r
n
al

1
aQ

r1tIU
Jt
t31
HClJI1
t
JIVU

i
rlUI

1o
ifm
ft
q
t

VI
31U
S
ltlod

bnM
UfO
l
W

kldf

CJiJi
ti

WIf
nl

L
llil
g

ncn
d

oressor

M
et

illpuntinl
botts
if

l9Wul
fb

i
l
fI
I
l

1Ttio
l

qqlJ

necessary
re

Ighten

I

d
210
Air

Conditioning

Tightening

torque

Flexible
hose
to

compressor

dl

t
kg
J
l

IQ

1

Tf
es

oriti
ra

Lbolts

IbP
fo
o15g

m
J

r
f6i
o
20
i
il

f

J

rt
I

r

aGket
engine

Dons
1
1

0

1
1
3
16

5

l11fd
1l

V

f

42
3
3U
llif

Yl

I
u

y
j

3
D
not

remove

IJgs
orflexibie

1i6
e
before

ready
for
immediate
use

4l
di

Wheniiinstallingccomptess
i
turn

it
serWfiPtiffies
SlOt

5
When

connecting
flexible

hose
to

9mPr
ssor

apD
v

a
coat
of
Hfresh

JU
UI

l1Il
t
2
JIUU
uOHltl
r
fl

compressor
0
1

to

fs
aHn
lurfaces
of

1n
1l11
JJ

J
f
PJU

Ht
UlUJ
jJ

joints

AC

26
5

1

Compressor
attachment

2

Compressor

3

Compressor
bracket

4
AHernator

5
Idler

pulley
bracket

AC745

Fig
AC
31

Removing
compressor

6
Evacuate

cooling
system
then
re

charge
with

refrigerant
Refer

to

Evacuating
and

Charging
System
under

l
r

Gen
efal

Servic
ectioo

f
iI
t

7
F

Whenever
remoV
J

compres
r

be
su
J

t8

C6itiu
t
Ua
t
st
make

idie

mV
i
1rJ

adjustril
rit
and

adjwt
beJf
tension

yv

1

r
Y

N
o
s

9

r
h

v

a

For

compressor
diive
belt

and

tOoling
fan
belt
tensions
refer

to

1
Ildlet

Yt
j
WI
c
S
t
q

b

Cheok

refrigerant

leakage
if

neces

sary
correct

dO
I
wl
Tw
l
rt

f
r2

iVl
2
i
l
n

U
l

bnu
1
1Z
2

gf

ign
rb

nojJ

2

IDLER

PULLEY

FAN
BELT
TENSION

ADJUSTMENT

The

standard

compressor
drive

belt

tension
is
between

8
and
12

mm

AC480

Note
Be

sure
to

loosen

locking
nut

before

turning

adjusting
bolt
Re

tighten
it

after

adjustment

REMOVAL
AND

INSTALLATION

Remove
drive

belt

To
do
this
loosen

locking
nut

before

loosening

adjusting
bolt
Drive

belt
will
then
be
detached

2

Remove
idler

pulley
from
bracket

by
r

J1e

vM
or
king
nut

jiwT
9ff
t

llil
reverse
the

order
of

rerr
oval
jldJ
1
t

Jldr

J
I

INSPECTiON

Oheck
idler

pulley
for

smooth
rota

tion

G
0

llfHt
H
Y

d
H

u
t
1
W

n
l

ot
Jrk
H
l

Check
i

ler

pulley
bracket
for

cracks

Replace
arts
iffound

damaged

c

f
lOJ

gD
IlI
J
l

gtt
flvlnv

nOj
IH

q
g

cll
dE
m
J

COOLING
UNIT

REMOVAL
AND
oM1

INSTALl
A

1lIONI
gnillslUli
n

dW
C

19qm91
crft

llU2
3

6rn
f01
Gl0ql

pj

nDiScoimecprlY
i

ferY
lgroUR
hable

2

Disbhargiou
y
tem

iRefrflsll
Qis

chargingrSystemiillidenGeneral
S

ervicel

sectiom5qiq
10
2
9
fl
1U
n
1Ii
2

oj
liD
Air

Conditioning

0
32
and
0
47
in

when

depressed

with
thumb

pressure
midway
between

the
crankshaft

and

compressor
pulleys

If

necessary
turn

adjusting
bolt

to

move
idler

pulley
up
or
down

until

belt

tension
is

correct

Idler

pulley

Crankshaft

pulley

AC456

Fig
AC
32

Adjustment
of
bolt
tension

3

Connect
low

and

high
pressure

pipes
to
their

proper
positions
in

engine
compartment

Notes

3
Be
sure

to
use
two

wrenches
when

connecting

pipe
joints

b

Plug
pipe

opening

immediately

after

pipe
disconnection

c
Be

careful
not
to

break

expansion

valve
This
valve
is

wrapped
with

heat

insulating
tape

0

J
JWu

J
1
2
ld

m

bm
Ufl

J51
8

I

1

lEldgJ
v
Jwm
j

y
d
n
l2u

1
C765

X

fIlO
1i

qJ
j

gnjlcfu2fIJ
lc
rf

1551

1UJ

flip
1h
tqnPfffi2n
Wfi

i
V1c
ip

j

at
3duJ

lsIliqr
J

wlr
v
n

irWfiqX
ani

qiq

4q
v
Remo
e

tworgromll
ets
from

dash

panel
lots
n

5
lRemove

glovelbox
lBl
n1

oT
0

6

Detach

cooling
unit

cover

Icyom
n

AC

ZA
AC766

Fig
AC
34

Removing
cooling
unit

cover

7

Remove
three
ducts

from

cooling

unit

i

j

l

I

11

AC767

Fig
A
C
35

Removing
cooler
ducts

8
Remove
thermo

switch
control

cable
from

conne
ctor

9
Remove

cooling
unit

and
bracket

as
an

assembly

J

t

AC768

F

lIJAh
Cr
P

3
6
R
1

7
fi
vorr

l
l51
r

Ig

emo
vmg
coo

mg
um

r

n
I1iBITJ
0HJ
Jl
t

rbtivl2

Ofm
IIfj

wom
51
f

H

f
L

ol

IJgjjJpn
1I
SH
tc

vehicle
bn

y
with
five
rews

q

2tl
G

i
O

r
Jv
a8f1l1

J
a

I
ld
1

51
b
nc

IOJni

QisconnecEf
twonleadliwif
eUcon
1

nectars
from

cooling
unitqiq
s
iuo
UHf

I

o

Fig
AC
37

Disconnectirt
connector
3

DISASSEMBLY
AND
ASSEMBLY

I
Remove
bracket
and
lead
wire

connector
main

relay
thermo
switch

resistor

motor
etc
from

cooling

unit

2

Remove
five
screws
and
duct

3
Remove
main

relay

4

Remove
thermo
switch

5

Remove
three
screws
and
five

springs
securing

upper
case
lower
case

and

rear
bracket

6
Unfasten

fittings
securing
inlet

and
outlet

pipes
Air

Conditioning

11
To
install

cooling
unit
reverse

the
order
of
removal

Notes

a

Apply
a
coat
of

fresh

compressor

oil
to

sealing
surfaces
when
COD

necting
pipe
joints

b
Use
two
wrenches
when
connecting

cooling
pipes

c
Evacuate
cooling

system
then
re

chaJge
with

refrigerant

Refer
fo

Evacuating
and

Charging

System
under
General
Service
see

tion

9

7

Upper
and
lower
cases
can
now

be

separated

8
Remove
motor
and
fan
as
an

assembly
Also
remove

evaporator

9
Peel
heat

insulating
tape
from

ex

pansion
valve
and
unfasten

clip
secur

ing
expansion
valve

capillary
tube
to

pipe

Remove

expansion
valve
from

evap

orator

10
To
install
reverse
the
order
of

removal

AG
28
d
Check

refrigerant
leakage
if
neces

sary
repair
Refer
to

Checking
for

Leaks
under
General
Service
sec

tion

Tightening
torque

Copper
tube

joint
nut

High

pressure
side
3

8
in

2
5
to
3
5

kg
m

18
to
25
ft
lb

Low

pressure
side
I

2
in

2
5
to
4
0

kg
m

18
to
29
ft
lb

00

L

1

Motor

2

Fan

3
Lower
case

4

Cooler
duct

5

Evaporator

6

Expansion
valve

7

Upper
case

8
Resistor

9
Main

relay

10
Thermo
switch

11
Cable
c

mp

12
Cable

3
Harness

AC725

Fig
A
C
38

Disassembling
cooling
unit

Expansion
valve

tightening

torque

5

kg
m
36
ft
Ib

Notes

a
When

installing
expansion
valve
on

evaporator
make
sure
that

temper

ature
oensing

capillary
tube
is
in
its

proper
position
on
outlet
side

b

Apply
a
coat
of
fresh

compressor

oil
to

sealing
surfaces
of

pipes

INSPECTION

Evaporator

Check

evaporator
for

leakage
or

damage
If

damaged
replace

Expansion
valve

Check

expansion
valve
for

leakage

or

clogging
If

clogged
clean
filter
in

expansion
valve
If

damaged

replace

RECEIVER
DRYER

AND

PIPING

REMOVAL
AND

INSTAUATION

Receiver
dryer

I
Disconnect

battery
ground
cable

2

Discharge
system
Refer
to

Dis

charging
System
under
General
Service

section

3

Disconnect

compressor
lead
wire

at

connector

4

Disconnect

cooling
pipes
at

joints

Acno

Fig
AC
39

Diaconnecting
coo

ing

pipes

Notes

a

Plug
all

piping

joints
immediately

after

pipe
disconnection
to

prevent

entry
of
dust
or
moisture
laden
air

into

receiver

dryer
or
air
aJOdi

tioning
system

b
Use

two
wrenches
when
dIsconnect

ing
cooling
pipes

5

Remove
four
screws

securing

receiver

dryer
bracket

to
vehicle

body

and
detach

compressor
relay
and

pres

sure
switch
as
an

assembly

6
To

install
receiver

dryer
and

piping
reverse
the
order
of
removal
Air

Conditioning

Notes

a

Apply
a
coat
of
fresh

compressor

oil
to

sealing
surfaces
when
con

necting
cooling

pipes

b
Use
two
wrenches
when

connecting

cooling
pipes

c

Evacuate

cooling
system
then
re

charge
with

refrigerant

Refer
to

Evacuating
and

Checking

System
under
General
Service

sec

tion

d
Check

refrigerant

leakage
if
neces

sary
repair

Refer
to

Evacuating
and

Charging

System
under

General
Service
See

tion

Condenser

Disconnect

battery

ground
cable

2

Discharge

system
Refer

to
Dis

charging
System
under
General

Service

section

3
Drain

engine
coolant

4

Remove
radiator

grille

5

Remove

radiator

shroud
and

radiator

On
automatic
transmission

models

disconnect
both

torque
converter
oil

hoses

Note

While

cooling
water
is
hot

take

precautions

against
scalding

6
Disconnect
two

pipes
from

con

denser
remove
two

screws

securing

condenser

Condenser

can
now
be

removed

AC485

Fig
AC

40

Removing
conden
er

Notes

a
Use

two
wrenches
when
disconnect

ing
pipe

joints

b

Plug
openings
immediately
after

disconnecting
pipes

7

To
install

reverse
the
order
of

removal

AC

29
Tightening
torque

Flare
nut
for

copper
tube

from

compressor

2
5
to
4
0

kg
m

i8
to
29
ft
Ib

Flare
nut

for

copper
tube

to
receiver

dryer

2
5

to
3
5

kg
m

i8
to
25
ft
lb

Notes

a
When

disconnecting
and

connecting

cooler

pipes
be
sure
to

use
two

wrenches

b

Apply
a
coat
of
fresh

compressor

oil
to

sealing
surfaces
when

con

necting
cooler

pipes

c

To

prevent

possibility
of

explosion

due
to

high

pressure
within

cooling

system
do

not
clean
condenser

with
steam

Always
use
cold
water

or

cold

compressed
air

d
Evacuate

cooling
system
then
re

charge
with

refrigerant

Refer
to

Evacuating
and

Charging

System
under
General

Service
sec

tion

e
Check

refrigerant
leakage
if
neces

sary
repair
Refer
to

Checking
for

Leaks
under
General
Service

sec

tion

INSPECTION

RecelYer

dryer

Check
for

refrigerant
leakage
or

damage

Check
for

proper
connection
of

two

lead
wires

running
to

pressure

switch

If

any
component

part
is
found

damaged
replace
receiver

dryer
and

pressure
switch
as

an

assembly

Condenser

I

Check

inlet
and
outlet

pipe
joints

and

sealing
surfaces
for

damage
Re

place
parts
if

damaged
or

leaky

2

Clogged
condenser
fins
or

air

pas

sages
may
reduce

cooling
efficiency
of

condenser
Clean
these

areas
with

dry

compressed
air

Piping

Check

piping
for

leakage
If

leakage

occurs
at
connections

retighten

connecting
nuts

Replace
if

leakage

persists