engine DATSUN PICK-UP 1977 Service Manual

Body
Electrical

System

EMISSION
WARNING
SYSTEM

California

models

CONTENTS

FLOOR
TEMPERATURE
WARNING

SYSTEM

California
models

DESCRIPTION

FLOOR

TEMPERATURE

WARNING
SYSTEM

California
models

DESCRIPTION

The
floor

temperature
warning

system
consists
of

a
floor

temperature

sensing
switch
installed
on

the
vehicle

floor
a

floor

temperature
relay
a

floor

temperature

warning
lamp
and

harnesses

When
the

floor

temperature
rises

to

an

abnormal
level

the

warning

lamp

will

come
on

to
call
the
attention

of

the

driver

i

f
FUSIBLE
LINK

P

BATTERY
IGNITION

SWITCH
BE
43

8E
43
WARNING
LAMP

TROUBLE

SHOOTING
GUIDE
BE
43

BE
44

The

warning

lamp
also
comes
on

during
operation
of

the

starter
motor

permitting
inspection
of

the

lamp
s

condition
The

lamp
goes
out
after
the

engine
starts

Refer

to
Section
EC
for

details

WARNING
LAMP

Bulb

replacement

I

Remove
cluster
lid

2

Twist

warni
ng

lamp
socket

Socket

with
bulb
can
then
be

taken

out

3
Pick

up
bulb
from
socket

IGNITION
RELAY

I
I
4

Installation
is
in
the

reverse
se

quence
of

removaL

Bulb

wattage

Floor

temperature

warning

lamp

17W

Lamp
body
replacement

I
Remove

cluster
lld

2

Disconnect
lead
wire
at
connee

tor

3

Remove
two
screws

retaining

lamp
body

4
Installation
is

in
the

reverse
se

quence
of

removal

FLOOR

I
l

I
SENSOR

RELAY

WARNING
I

LAMP
FLOOR
SENSOR

ON

FLOOR

TEMPERATURE

LOW

OFF
FLOOR

TEMPERATURE

HIGH

7

BE697B

Fig
BE
64
Circuit

diagram
of
floor

temperature
warning

system

BE
43

OUTLINE
OF
AIR
CONDITIONER

REFRIGERATION

SYSTEM

CONDENSER

COMPRESSOR

RECEIVER
DRYER

COOLING
UNIT

ELECTRICAL
CIRCUIT

OUTLINE
OF
AIR

CONDITIONER

The

air
conditioner
consists

es

sentially
of
a

cooling
unit

compressor

condenser
receiver

dryer
and

piping

The

cooling
unit

secured
with

three

brackets
is
a

ttached
to
the

location

occupied
by
the

package

tray

in
the
dash

panel

The

cooled
air
from
the
duct

is

directed
into
the

passenger
compart
Air

Conditioning

DESCRIPTION

CONTENTS

AC
2

AC3

AC
3

AC3

AC4

AC4

AC
5
DESCRIPTION

MAIN

RELAY

FAN
SWITCH

THERMO

SWITCH

PRESSURE
SWITCH

COMPRESSOR
RELAY

F
I
C
D

SOLENOID
VALVE
AC
5

AC
7

AC
7

AC
7

AC
7

AC
7

AC
7

ment

through
the
three

outlets
at

the

instrument

panel

The

compressor
serves
to

compress

the

vaporized
refrigerant
and
is
attach

ed

through
the
bracket
to
the
loca

tion

occupied
by
the

mechanical
fuel

pump
on
the

engine

The
condenser
cools
the

compres

sed

refrigerant
vapor
sent

by
the
com

pressor
and
is

located
on

the
front
of
the
radiator
in

the

engine
compart

ment

The
receiver

dryer

serving
as
a

reservoir

for

storage
of
the

liquid
sent

by
the
condenser
is

located
on
the

right
in
the

engine
compartment

The

piping
consists
of

two
flexible

hoses

and
five

copper
tubes
which

connect
various

components
of
the

air

conditioning
system

I

Cooling
unit

2

Expansion
valve

3
Receiver

dryer

4

Comressor
5

Condenser

6
Duct

@
Flexible
hose

@
Copper
tube

AC
2
AC724

Fig
AC
1

Cooling
system

REFRIGERATION

SYSTEM

If

you
were
to

paint
your
finger

with
alcohol

your
finger
would
feel

cold
This
is
because
the

liquid
alcohol

takes
heat

away
from

your
finger

while
it

evaporates
If
a

quickly
evapo

rating

liquid
such
as
alcoliol
is

placed

in
a
container
inside
a
box
the
tem

f

Outside
air

U

Condenser

J6G1
i
i

1
1

t1

1

ilill
I
I

J

JJ
LlJ
i
l

7

U

Receiver

dryer

h

w

t

CONDENSER

The
condenser
is
installed
to
the

front
of
the
radiator

The
heated
and

compressed

refrigerant
gas
from
the
Air

Conditioning

perature
inside
the
box
will

drop
This

is
because
the

alcohol
is

evaporated

absorbing
the
heat
from
the
air

insidc

the
box
If
the

gaseous
alcohol
is

collected
and

cooled
with

cold
water

it
will
be

changed
back

into
a

liquid
by

absorption
of
its
heat

by
the
cold

water

The
cooler

operates
on
this

princi

Compressor

t

q
ttLJ

IrJ

Evaporator
It

J

1

J

f
9

d

lUr

I

Expansion
valve
V7777
J
High
pressure

lLLLLL
l

gas

I
I
High
pressure

liquid

t

u

compressor
condenses
to
a

liquid
by

being
cooled

by
air

passing
between

the
fins
of
the
condenser

1
GJ
7

vlmnn

iii

plI

d1i
1il

Ac459

Fig
AC

3
Condenser

AC3
pIe
The

liquid
used

is
the

refrigerant

R
12

The
heat
inside
the

passenger

compartment
is
absorbed

by

changing

the

refrigerant
from
a

liquid
to
a

gas

and
then

dissipated
to
the

outside

by

changing
the

refrigerant
from

a

gas

back
to
a

liquid

The

refrigeration
system
is

shown

in

Figure
AC
2

Low

pressurt

liquid

1

I
L2
Low

pressure

gas

Inside
air

li

r

L

Blower
motor

AC458

Fig
AC
2

Refrigeration
cycle

COMPRESSOR

The

compressor
is
installed
to
the

side

of
the

engine
and
is
driven

by

crank

pulley
through
a
belt
The

refrig

erant

gas
leaving
the

evaporator
is

forced
out
to
the
condenser

by
com

pressor
and
the
low

pressure
refrig

erant

gas
is

compressed
to
a

high

pressure
and

high

temperature

The

driving
force
is
transmitted

by

an
electrical
clutch
Because

engine

rpm
is

very
low

during
idling
the

clutch
will

not
transmit

the

driving

force
thus

ensuring
smooth

engine

idling

The

refrigerant
within
the

thermo

bulb

changes
in

pressure
through
the

super
heat

condition
of

vaporized
re

frigerant
gas
which
comes
out
of
the

evaporator
causing
the

deflection
of

the

diaphragm
The
lift

of
the

ball

valve
attached
to
the

diaphragm
is

changed
by
the
deflection
of
the
dia

phragm
thus

controlling
the
amount

of

refrigerant
passing
the

orifice

ELECTRICAL
CIRCUIT

DESCRIPTION

The

electrical
circuit

of
the
air

conditioner
consists
of
four
switches

two

relays
a
solenoid
valve
a
fan

motor
and
a

compressor
magnetic

clutch
Air

Conditioning

Diaphragm

Orifice

Valve
ball

AC729
4

Sensing
bulb

Fig
A
C
6

Expansion
value

The

following
wiring
diagram

pro

vides
a

complete
description
of
the

whole
circuit

When
the

ignition
switch
and
the

fan
switch
are
ON
the
main

relay
is

activated

causing
battery
power
to

flow

through
the
fan
motor
and
the

magnetic
clutch
The

magnetic
clutch

is

activated

by
the
thermo
switch

AC
5
000

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

II
Cable

clamp

12

Cable

13
Harness

AC725

Fig
AC
7

Cooling
unit

pressure
switch
and

compressor
relay

The

blower
motor
fan

speed
is

con

trolled

by
the
fan
switch
and
resistor

The
solenoid
valve
is

also
activated

This
in
turn

causes
the

fast
idle
control

device
F
l

C
D
to
increase

engine

speed
when
the

vehicle
is

at
rest
with

the

engine
ON

MAIN
RELAY

The
main

relay
is
located
on
the

cooling
unit

When
the

ignition
switch
and
fan

switch

are
both
turned
on
the

COll

@

FAN
SWITCH

The

fan
switch

serving
as
a
control

unit
is

installed
on
the
center
console

This
switch

controls
the

blower
motor

speed
through
the
resistor
It
is
also

used
as
a

main

relay
switch

Fig
AC
I0
Fan
switch

THERMO

SWITCH

The
thermo

switch
is

located
on
the

upper
side
of
the

cooling
unit
and
is

controlled

by
the

cable
and
the
con

trollever
attached
to
the
console
box

It
is
so

designed
that
when
the
air

passing

through
the

evaporator
core
is

cooled
down

to
the

predetermined
Air

Conditioning

tacts
in
the

relay
are
closed
Then

electrical

power
from
the

battery
is

supplied
to
the
blower

motor
and
the

electrical
clutch
for
the

compressor

@

Dc

IDe

ID
1
1

l@

@
e

L
J

AC465

Fig
A
C
9
Main

relay

temperature
set

by
the

control
lever

it

automatically
turns

off
When
the

switch
is
turned
off
the

magnetic

clutch
is

turned
off

stopping
the
flow

of

refrigerant
inside
the

cooling
system

and

increasing
the

cooling
system
tem

perature

When
the

air
rises
to
the

pre

determined

temperature
the
thermo

switch

automatically
turns

on
In
this

way
the

temperature
of
the
air
dis

charged
from
the

cooling
unit
is
auto

matically
controlled
as
desired

PRESSURE

SWITCH

The

pressure
switch
is
turned
off

when

refrigerant
pressure
in
the

cooling
system
rises
to

an

abnormally

high
level
28

kg
cm2

398

psi
This

in

turn
turns
off
the

compressor

magnetic
clutch

actuating
the
com

pressor
relay
and

gradually
decreasing

pressure
in
the

cooling
system
When

the

pressure
drops
to
or
below
24

kg
cm2
341

psi
the

pressure
switch

again
turns
on

Thus

cooling

system
refrigerant

pressure
is

automatically
maintained
at

the

proper
value

a
t
all
times

AC
7
COMPRESSOR
RERAY

The

compressor
relay
is

attached
to

the
receiver

dryer
bracket
on
the

right

side

of
the

engine
compartment
This

relay
is

actuated
by
the

fan
switch

thermo
switch

and

pressure
switch
to

turn
on

and
off
the

compressor

magnetic
clutch

cv

1

2

AC731

Fig
A
C

11
Pressure
switch
and

compressor
relay

F
I
C
D
SOLENOID
VALVE

The
F
l
C
D
solenoid

valve
is
at

tached
to
the
dash

panel
in
the

engine

compartment
This
valve

supplies
vacu

um
to
the

F
I

C
D

diaphragm
through

the
vacuum
hose
connected

to
the

engine
intake
manifold
when
the

engine
is

at
idle
and

the

cooling
system

is
ON

thereby
raising
idle

speed
to
the

predetermined
rpm
800

IW

r

e

I

1
s

AC132

Fig
AC
12
F
l
C
D
solenoid

value

REFRIGERAi
H
R
12

COMPRESSOR
OIL

MAINTENANCE

PERIODIC
MAINTENANCE
AND

SEASON
IN

INSPECTION

GENERAL
SERVICE
INSTRUCTION

SAFETY

PRECAUTIONS

EV

ACUA
TlNG
AND

CHARGING
SYSTEM

HANDLING

MANIFOLD
GAUGE

HANDLING
SERVICE
VALVE

HANDLING
CAN
TAP

DISCHARGING
SYSTEM

REFRIGERANT
R
12

The

refrigerant
used
in
the
air

conditioner
is

generally
called
Re

frigerant
12

R
12
No
other

refrig

erant
than
the

above

refrigerant
should

be
used

This

refrigerant
is

usually
available

in
a
small
can
or
a

cylinder
In

either

case
it

is

liquefied
under

high
pressure

in
the
container

Refrigerant

evaporates
easily
has
a

low

evaporation
point
and
moreover

since
the
latent

heat
of
the

refrigerant

is

large
it

can
abSorb

a

large
amount

of
heat

wh

err
e

vaporating
Extreme

care
must
be
exercised
when

handling

the

refrigerant

COMPRESSOR
OIL

The
SUNISO
5GS
or
SUNISO

351

should
be
used
as

refrigeration

lubricant

Mixing
of
the

two
is

allowable

The

refrigeration
lubricant
should

be
used
to
assure
the
successful
com

pressor
operation
Use
of
oils
other

than
recommended
or

mixing
of
the

oil

with
other
oils
would
cause

chemical
reaction

or
lead
to
lowered

viscosity
or
deficient
lubrication

The
oil

absorbs
moisture
as
it

con

tacts

the
air
This

points
out
the
need

for

care
not
to

expose
it

to
atmos

phere
for
an

extended

period
of
time
Air

Conditioning

GENERAL
SERVICE

CONTENTS

EVACUATING
SYSTEM

CHARGING
REFRIGERANT

CHECKING
FOR
LEAKS

HALIDE
LEAK

DETECTOR

ELECTRIC
LEAK

DETECTOR

REFRIGERANT
LEVEL
CHECK

SIGHT

GLASS

PERFORMANCE
TEST

COMPRESSOR
OIL
LEVEL
CHECK

PERFORMANCE
TEST

REFRIGERANT

LEAKS
AC
8

AC

8

AC
8

AC
8

AC
8

AC
9

AC
9

AC
9

AC10

AC

11

AC
12

MAINTENANCE

PERIODIC
MAINTENANCE

AND

SEASON
IN

INSPECTION

Both

periodic
maintenance
and

season
in

inspection
are

most
essential

to
enable
the
air

conditioner
to

give

full

performance

Perform
the

following
checks

Start

engine
and

check

refrigerant

level

through
sight
glass
on

receiver

dryer
For

details
refer
to

relative

topics
under

Refrigerant
Level

Check

2
Check
the
entire

sysiein
for

sign

of

refrigerant
leaks

Refer
to
relative

topics
under

Checking
for

Leaks

and

Refrigerant
Leaks

If

any
trace
of
oil
is

noted
at

and

around
connection

fittings
it
is
a

sure

indication

that

refrigerant
is

leaking

This
condition

can
be
corrected

easily

by
retightening
the

joints
If

any
joint

on
line

is

suspected
of
small
amount
of

leakage
use
a
leak

detector
to

locate

leaking
points

3
Check

compressor
drive
belts

for

proper
deflection

Season
off

Observe
the

following
maintenance

tips
to
allow

the
air

conditioner

to

operate

normally
in

the
next

season

I

Keep
the
entire

system
free
from

AC
8
AC12

AC

13

AC15

AC15

AC16

AC

16

AC16

AC
17

AC17

AC
17

AC18

refrigerant
leakage
by

periodically

checking
for

refrigerant
gas
leak

even

out
of
season

2

Turn
the

compressor
for
10

minutes

at
least
once
a
month

by

running
the

engine
at
1

500

rpm

c
ENERAL
SERVICE

INSTRUCTION

The

servicing
of
the
air
conditioner

should
be
carried
out

only
by
well

trained
servicemen
This

chapter
de

scribes
essential

points
of

servicing

Jf

a

Jarge
amount
of

dirt
and
sand

enter

the

system
they
will
be

carried
with

refrigerant
and

may

clog
the

system
or
scratch

rotating

parts
This

points
out
the
need
for

care
in

servicing
the

system
That

is

disconnecting

joints
should
be

carried
out

in
a
dean

place

Water
should
not
be
allowed
to

get

inside
the

system
The

refrigerant

does
not

readily
mix

with
water

However
the

presence
of
even
a

minute

amount
of

water
will
cause

a
chemical
reaction

at

high
tem

perature
which
will
in

turn

produce

hydrochloric
acid

HCl
Since

hydrochloric
acid
is

highly
corro

sive
to
metals
the
aluminum
and

copper
piping
etc
will
become

corroded
and
the

refrigeration

system
will
become

clogged

Air
Conditioning

b

When

charging
hquefied
refrigerant

into
the

system
lith
the
can
turned

upside
down
to
reduce

charging

time

charge
it

only
through
high

pressure
valve
but
not

through
low

pressure
3
h
e

After

completion
of

charging
the

compressor
should

always
be

turn

ed
Several
times

manually
See

Figure
AC
22

t

UL
Q

v1ifl
j

AC739

Fig
A
C
22

ClUJrging
refrigerant
First

step

4
If

refrigerant
charging

speed
slows

down

charge
it
while

Iunning
the

compressor
for
ease
of

charging
After

having
taken
the

steps
up
to

3
above

proceed
with

charging
in

the

following

order

I
Shut
off

high

pressure
valve
of

manifold

gauge
back
into

refrigerant
can
and
can

may
explode

2

Run
the

engine
at

idling
speeds

about
1
500

rpm

3
Set
the

temperature
control

lever
and
fan
switch

at
maximum

cool

and
maximum

speed
respectively

4

Charge
refrigerant
while
con

trolling
low

pressure
gauge
reading
at

2
8

kgfcm2
40

psi
or
less

by
turning

in
or

out
low

pressure
valve
of
mani

fold

gauge
See

Figure
AC
23
Caution
Never

charge
refrigerant

through
high

pressure
side
of

sys

tem
since
this
will
force

refrigerant

t

AC740

Fig
A
C
23

Charging

refrigerant
Second

step

AC
14
5
When

refrigerant
can
is

empty

fully
close

both
Ives
of
manifold

gauge
and

replace
refrigerant
can
with

a

new
one

Before

opening
manifold

gauge

valve
to

charge
refrigerant
from
new

can

be
sure
to

purge
air
from
inside

charging
hose

6

Charge
the

specified
amount

of

refrigerant
into

system
by
weighing

charged
refrigerant
with
scale

Over

charging
will

cause

discharge

pressure

to

rise

AC255

Measure
the

amount
of

charged

refrigerant
with
a
scale

Make
a

note
of
the

amount

charged

from

can

Fig
AC

24
Measuring
refrigerant

Refrigerant
capacity

Unit

kg
lb

Refrigerant
Minimum

Maximum

R
12

0

7
1
5
0
9
2

0

Note
The

presence
of
bubbles
in

sight
glass
of

receiver

dryer
is
an

unsuitable
method
of

checking
the

amount

of

refrigerant
charged
in

system
The
state
of
the
bubbles
in

sight
glass
should

only
be
used
for

checking
whether
the
amount
of

charged
refrigerant
is
small
or
not

The
amount
of

charged
refrigerant

can
be

correctly

judged
by
means

of

discharge
pressure
Refer
to
Re

frigerant
Level
Check

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

Notes

a
The
bubbles
seen

through
the

sight

glass
are
influenced

by
the
ambient

temperature
Since
the
bubbles
are

hard
to
show

up
in

comparatively

low

temperatures
below
200C
6S0

F
it
is

possible
that

a

slightly

larger
amount
of

refrigerant
would

be
filled
if

supplied
according
to

the

sight
glass
Be

sure
to
recheck

the
amount
when
it

exceeds
200C

680F
In

higher
temperature
the

bubbles
are

easy
to

show

up

b

When
the

screen
in
the

receiver

dryer
is

clogged
the
bubbles
will

appear
even
if
the
amount
of

refrig

erant
is
normal
In
this
case
the

outlet
side

pipe
of
the
receiver

dryer
becomes

considerably
cold

PERFORMANCE
TEST

Check
for
the
amount
of

refrigerant

in
the

system
can
be

made

by
meas

uring

pressure
on

discharge
side

The

correct
amount
of

refrigerant
is

in
the

system
if

pressure
on
the

discharge
side
is
within

the

specified

range
For
details
refer
to

Perform

ance

Test
described
later

Overcharging
will
show

up
in

higher

pressure
on
discharge
side

COMPRESSOR
OIL

LEVEL

CHECK

The
oil

used
to
lubricate

compres

sor
circulates
into

system
from
the

oil

sump
while

c9mpressor
is

operating

The

efore
to

correctly
measure
com

pressor
oil
the

amount
of
oil

flowing

to

system
must
be

considered
If
a

considerable
amount
of

leakage
of

refrigerant
gas
happens
the

leakage
of

compressor
oil
is
also
considered

There

will
be

no

compressor
oil
leak

age
from
a

completely
sealed

system

When

system
operates
under

satisfying

condition
the

compressor
oil
level

check
is

unnecessary

When

checking
the
level

of
com

pressor
oil
or

when

replacing
any

component
part
of
the

system
use
the

following
service

procedure
This

fa

cilitates
to
return
oil
to

compressor

I

Operate
compressor
at

engine

idling
speed
1
000

rpm
or

below

with
controls
set

for
maximum

cooling
Air

Conditionin
j

and

high
blower

speed
for
10
to

15

minutes
in

order
to
return

compressor

oil
to

compressor

2

Stop
the

engine
and

discharge

refrigerant
of

system
and
then

remove

compressor
from

the
vehicle

3
Remove

compressor
fIller

plug

Drain

compressor
oil
from

compres

sor
oil

sump
and

measure
the

amount

4

Compressor
oil
is

satisfactory
if

the

following
amount
of
oil

remains
in

the

compressor

Residual
oil

S5
to
128

gr
3
to
4
oz

5
Check
the
cleanliness
of
the
oil
If

the
oil
contains

chips
or

other

foreign

material
clean
oil

5ump
with
new

oil

6
Discard
the

used
oil
and

fili
with

the
same
amount
of
new
oil
Add

oil
if

found
less
than
above
amount

Fig
AC
27

Filler

plug

If

compressor
is

inoperative
due
to

faulty
compressor
or

heavy
loss
of

refrigerant
remove

compressor
and

repair
as

necessary
Then

pour
oil

up

to
correct
level
and
install
on

engine

After
above

steps
have
been

complet

ed
recheck
oil
level
drain
oil
to

correct
level
if

level
is

excessively
high

PERFORMANCE
TEST

The
cooling

performance
of
the
air

conditioner

changes
considerably
with

changes
in

surrounding
conditions

Testing
must
be

performed
using
the

correct
method
This

test
is
used
to

judge
whether

system
is

operating
cor

rectly
and

can
also
be
used

as
a

guide

in

checking
for

problems

I

Park
the
vehicle
indoors
or
in
the

shade

AC
17
2

Open
all
the
windows
of
the

vehicle
fully
However

close
the

doors

3

Open
the
hood

4

Connect
manifold

gauge
to

high

and
low
side
service
valves
of
the

system
Refer
to

Handling
Manifold

Ga

uge

5

Set
fan
control
lever
to
maxi

mum

6
Set

temperature
control
lever

to

max
cool

position

7
Start
the

engine
and
hold

engine

speed
at
1
500

rpm

S
After
the
air

conditioner
has
been

operated
for
about
10
minutes

measure

system

pressures
at

high
pres

sure

discharge
side
and
low

pressure

suction
side

9
Measure
the

temperature
of
dis

charge
air
at

outlet

grille

10
Measure
the

temperature
of

capin

11
Measure
ambient

temperature

and

humidity
one
meter
3
3
ft

away

from
condenser
front
Be

careful
not

to

expose
dry
buib

and
wet
bulb

to

direct

sunlight

12
Check
for

any
abnormalities

by

comparing
the
test

results
with
stand

ard

pressure
in
Performance

Chart

Notes

a
The

pressure
will

change
in
the

followi

g
manner
with

changes
in

conditions

When

blower

speed
is

low
dis

charge

pressure
will

drop

When
the
relative

humidity
of
in

take
air
is
low

discharge
pressure

will

drop

b

The

temperature
will

change
in
the

following
manner
with

changes
in

conditions

When
the
ambient
air

temperature

is

low
the
outlet
air

temperature

will
become
low

If
the
test
reveals
that
there
is

any

abnormality
in

system
pressure
isolate

the

cause
and

repair
by
reference
to

the
Trouble

Diagnoses
and
Cor

rections

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