1977 DATSUN PICK-UP air conditioning

3

Piping

Flared
section
of

high
pressure
and

low

pressure
flexible

hose

Pipe
connections

rvice

valve

4

Evaporator
housing

Jnlet
and

outlet

pipe
connections

Expansionvalve

ELECTRIC
LEAK
DETECTOR

for
the

operational
procedures

refer
to

the
instructions
furnished
with

each
electric
leak
detector

Amount

of

refrigerant
Air

Conditioning

REFRIGERANT

LEVEL
CHECK

SIGHT
GLASS

Sight
glass
is

provided
at
the

top
of

receiver

dryer
One

guide
for
whether

there
is

enough
refrigerant
in

system
is

given
by
observing

refrigerant
flow

through
sight
glass
However
this

method

is
unsuitable
for

judging
the

amount
of

refrigerant
The
correct

refrigerant
level

can
be

judged
by

measuring
t
e

system
pressures
in
ac

cordance
with
the

procedures
de

scribed
Performance
Test

I

Start
the

engine
and
hold

engine

speed
at
1
500

rpm

Almost
no

reftigerant

Check
item

Temperature
of

high
pressure

and
low

pressure
pipes
Almost
no
difference

between

high

pressure

and
low

pressure
side

temperature

Bubbles
flow
continu

ousty
Bubbles
will

disappeu
a
nd
some

thing
like
mist

will

now
when

rerrigeran

is

nearly
gone
State
insightglass

A

I
I

AC256

Pressure
of

system
High
pressure
side

is

abnormally
loW

Repa
ir
Stop

compressor
and

conduct
an
overall

check
Insufficient

High
pressure
side
is

warOl
and

low

pressure

side

is

fairly
cold

The
bubbles
are
seen

at
intervals
of
1
2

seconds

A

r

I

AC257

Both

pressures
on

high

and
low

preS
ure
sides

are

slightly
low

Check
for

gas
leakage

repair
as

required
re

plenish
and

charge

system

AC

16
2

Set

temperature
control
lever
to

maximum

position

3

Set
blower
to
maximum

speed

4

Check

sight
gla
after
the

lapse

of
about
five

minutes
Judge
according

to
the

following
table

AC741

Fig
AC
26

Temperature
control
lever

Suitable
Too
much

refri
crant

High
pressure
side
is

hot
and
low

pressure

side
is
cold
High

pressure
side
is

abnormally
hot

Almost

transparent

Bubbles

may
appear

when

engine

speed
is

raised
and
lowered
No
bubbles
can
be

seen

No
clear
difference
exists
between
these
two

conditions

M

II
I

AC258

Both

pressures
on

high

and
low

pressure
sides

are
normal
Both

pressures
on

high

and
low

pressure
sides

are

abnormally
high

Discharge
reft

gerant

from

service
valve
of

10
11

pressure
side

Air

Conditioning

TROUBLE
DIAGNOSES
AND
CORRECTION

CONTENTS

COOLING
DIAGNOSES

FUNCTION
TEST

STANDARD
PERFORMANCE

PERFORMANCE

TEST
DIAGNOSES
AC19

AC
20

AC
20

AC21
COMPRESSOR

DIAGNOSES

NOISE

DIAGNOSES

BLOWER
MOTOR

DIAGNOSES
AC
22

AC23

AC24

COOLING
DIAGNOSES

INSUFFICIENT
COOLING

I

I

Check
amount
of

discharged
air

j

If
OK
No
or
insufficient

discharged
air

Performance
test

Refer
to

performance

test
on
the

following

page
1

ChecK
blower

I

I

I
If
OK

I

I

Repair
cooling

unit
Blower

stops
Check

sight
glass
for
bubbles

I

I

Many
bubbles

I

I
No
or

few
bubbles

Check
refrigeration
line

for

leakage

Note
If
there

are
too

many
bubbles

stop
compressor
and

check
for

leaks

Then

evacuate
and

recharge

system
Refer
to

Blower
motor

diagnoses

I

If

OK
lfleaks

Discharge
the

system

Evacuate

and

recharge
Repair
leaks
and

recharge

AC
19

FUNCTION
TEST

STANDARD
PERFORMANCE

The
air
conditioner
on
the

model

620

has
the
below

performance
char

acteristics
when
all
systems
are
in

good

condition

Compressor
pressure
is

also

indicated
below

N

E
24

j
23

22

21

20

19

18

17

16

15

14

13

I

12

u

0

6
0

5
0

4

0

3
0

2
0

1
0

20
25
30
35
40
45

Temperature
of
outside
air

ENGINE

FAN

TEMP
1

500

rpm

MAX

Fun
Cotd

20
15
10
5
0

Oc

Temperature
of

dischuge
air
Air

Conditioning

TEMPERATURE

Intake
In
the
cabin

Discharged
air
Pressure

160C
61
OF
30C
37OF
12

kg
cm2
170

psi

ISoC

64OF
50C
4IOF
13

kg
cm2

185
psi

220C
72OF
70C
45OF
15

kg
cm2
213

psi

270C

SIOF
100C
SOOF
IS

kg
cm2
256

psi

Note

Engine

FAN

TEMP
1

500

rpm

3

position

Cold
Max

REFRIGERANT
PRESSURE

Temperature
outside
Pressure

discharge
0

a

250C
77OF
18

kg
cm2

256

psi

Oc

35

300C
S6OF
15

kg
cm2
213

psi
u

Co

S

13

kg
cm2
IS5

psi
30

350C
95OF

25
400C
J05OF
J2

kg
cm2
170

psi
Pressure
suction

1
0

kg
cm2

14
psi

1
2

kg
cm2
17

psi

1
4

kg
cm2
20

psi

1

6

kg
cm2
21

psi

20

IS

AC
20

Air

Conditioning

PERFORMANCE
TEST
DIAGNOSES

Condition

Discharge
air
too
warm

a
Both

discharge
and
suction

pres

sure
too

high

b
Both

discharge
and
suction

pres

sure
too
low

c
Discharge

pressure
too

high
and

suction

pressure
too
low

d
Suction

pressure
too

high
and

discharge

pressure
too
low

e

Discharge

pressure
normal
and

suction

pressure
too

high

t
Discharge

pressure
normal
and

luction

pressure
too
low

g
Suction

pressure
normal
and

discharge
pressure
too

high

h
Both

discharge
and
suction

pres

sure
normal

Air

conditioning
is

operating

properly

Discharge
air
normal

or
too
cold

a

Discharge
pressure
normal
and

suction

pressure
too
low
Probable
cause

Air

mixed
with
refrigerant
in

system

Overcharge
of

refrigerant

Loose
fan
belt
or

engine
over

heating

Obstructed
or

dirty
condenser
fins

Insufficient

refrigerant
charge

Over

filling
of

compressor
oil

Damaged
compressor
valve
or

pack

ing

Loose

compressor
drive
belt

Clutch

slippage

Faulty
expansion
valve

Clogged
expansion
valve
strainer

Water
has
frozen
at

expansion

valve

Faulty
expansion
valve

Faults
of
both

a
and
h
exist

Air
leaks
from

engine
com

partment

Restricted
air
flow

through
evapo

ratof

Slow
blower
motor

speed

AC
21
Corrective
action

Evacuate
and

charge
system

Discharge
some
of

refrigerant
to

correct
level

Adjust
fan
belt
or
check

cooling

system

Clean
exterior

surface
with
water

Add

refrigerant

Drain
oil
and
correct
oil
level

Refer

to

Compressor
oil
level

check

Repair
or

replace
compressor
Refer

to

Compressor

Adjust

Repair
Refer
to

Compressor

Reinstall

sensing
bulb
correctly
to

keep
it

tight
to

pipe

Replace

Clean
strainer

Evacuate
and

charge
system

Replace

Correct

sealing

Clean

evaporator
fins

Check
and

repair
blower
motor
and

wiring

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