1977 DATSUN PICK-UP warning light

r

CHECKING
B
C

D
D

SOLENOID
VALVE

I
Turn
on

engine
key
Do
not
start

engine

2
Ensure
that
solenoid
valve

clicks

when

intermittently
electrified
as

shown
in

Figure
ET
37

Fig
ET

37

Checking
solenoid
uolV
l

I

l

EF264

2

Turn

ignition
key
to
ON

posi

tion

3

Ensure
that
tester

pointer
deflects

when

ignition
key
is

turned
on

4

If

tester

panter
does
not
deflect

when

solenoid
valve

and

speed
detect

ing
switch

circuits

are

functioning

properly
amplifier
is

faulty
Engine
Tune

up

3
If
a

click
is

heard
solenoid
valve

is
normal

4

If
a
click
is
not
heard

at
all
check

for

continuity
with
a
circuit

tester
If

discontinuity
is

detected

replace
sole

naid
valve

CHECKING

AMPLIFIER

Manual
transmission

models

The

amplifier
is

installed
at
the

rear

of
the

speedometer
To

check

proceed

as
follows

1
Set
circuit

tester
in

d
c

ampere

range
IA

min
full
scale

connect
test

probes
of
tester
as

shown
in

Figure

ET
38

Do

not
confuse

positive
line

with

negative
line

M

p
1

II

L
o

A

I
of

j
t
J

f

T

1

Ignition
key

2

Amplifier

3

Speed

detecting
switch

4
B

C
D

D

solenoid
valve

Fig
ET
38

Checking

amplifiu

REPLACING
AIR

PUMP
AIR
CLEANER

ELEMENT

Remove
air

hose
then
detach
air

cleaner
from

hoodledge
Air
cleaner

element

and
air

cleaner
lower

body
are

built
into

a
unit
construction

Replace

air

cleaner
element
and
lower

body
as

an

assembly

ET

20
EC323

Fig
ET
39

Repl4cing
air
cleaner

element

CHECKING

EXHAUST

GAS

RECIRCULATION

E
G

R

CONTROL

SYSTEM

Checkln

E
G
R
control

system
In
Ita

mounted

condition

I

M
ake
a

thorough
visual
check
of

E

G
R
control

system
If

necessary

wipe
away
oil
to

facilitate

inspection

If

hoses
are

cracked
or

broken
fe

place

2
With

engine
running
check

E
G
R

warning
system
for

proper

function
Make
sure
that
E

G
R
warn

ing
lamp
light
when

ignition
switch
is

turned
to
START

position
starter
mo

tor
runs
If
E
G
R

warning
lamp
does

not

light
inspect
harnesses
and
con

nectors
or

replace
warning
lamp
Then

turn

ignition
switch
to

ON

position

and
check
the

following
items

I

If
odometer
of
detector
drive

counter
has
not
reached
50

000

counts
make
sure
that
E

G
R

warning

lamp
does
not

light

2

If
odometer
of
detector
drive

counter
has
attained
50

000
counts

make

sure
that
E

G
R

warning

lamp

lights

If

warning

lamp
does
not

light

check
harnesses

connector
and
de

tector
drive
counter

replace

warning

lamp
or
detector
drive

counter
if

necessary

Note

Operation
of
E

G
R

warning

lamp
is

as
follows

3
If
there

is
a
leak

remove

top

cover
from

purge
contiol
valve
and

check

for
dislocated
or

cmcked
dia

phragm
If

necessary
replace
dia

phmgm
kit

which
is
made

up
of
a

retainer

diaphragm
and

spring

I
@

1
Cover

2

Diaphragm

3
Retainer

4

Diaphragm
spring

Fig
ET
47
ET350

Carbon
caniater

purge

control
valve

Carbon
unlster

filter

Check
for
a
contaminated

element

Element
can
be
removed
at

the

bottom
of
canister

installed
on
vehicle

body

Fig
ET
48

Replacing
carbon

canister

filter

Fuel
tank

vacuum
relief

valve

operation

Remove
fuel
filler

cap
and
see
it

functions

properly

I

Wipe
clean
valve

housing
and
have

it
in

your
mouth

2

Inhale
air
A

slight
resistance

ac

companied
by
valve
indicates
that

valve
is
in

good
mechanical
condition

Note
also
that

by
further

inhaling
air

the
resistance
should
be

disappeared

with
valve
clicks
Engine
Tune

up

3
If
valve

is

clogged
or
if
no
resist

ance
is

felt

replace
cap
as
an
assem

bled
unit

r

u

ET369

Fig
ET
49
Fuel

filler
cap

CHECKING

CATALYTIC

CONVERTER

INSPECTION

Preliminary
inspection

Visually
check
condition
of
all

component
parts
including
hoses

tubes
and
wires

replace
if

necessary

Refer
to

Inspection
of
A
I

S
on

page
EC
17

Catalytic
converter

Whether

catalytic
converter
is
nOf

mal
or
not
can
be
checked

by
ob

serving
variation
in
CO

percentage

The

checking
procedure
is

as
follows

Apply
parking
brake
Shift

gears

into

Neutral
for
manual
transmission

and
Neutral
or
Park
for
automatic

transmission

1

Visually
check

catalytic
converter

for

damage
or
cracks

2
Remove
air

hose
between
5

way

connector
and
air

check
valve

Plug
the

disconnected
hose
to

prevent
dust

from

entering
Refer
to

page
ET
12

3
Check
carburetor

pipes
for

proper

connection

4

Warm

up
engine
sufficiently

5
Race

engine
1
500
to
2
000

rpm

two

or
three
times
under
no
load
then

run

engine
for

one
minute
at

idling

speed

6

Adjust
throttle

adjusting
screw

until

engine
attains
to

specified
speed

Refer
to

page
ET
12

7

Check

ignition
timing
If

neces

sary

adjust
it
to

specifications
Refer

to

page
ET
10

ET
23
8

Adjust
idle

adjusting
screw
until

specified
CO

percentage
is

obtained

Refer
to

page
ET
12

9

Repeat
the

adjustment
process
as

described
in

steps
5
to

8
above
until

specified
CO

percentage
is

obtained

Note

Adjustment
in

step
9
should
be

made
ten
minutes
after

engine
has

warmed

up

10
Race

engine
1
500
to
2
000

rpm
two
or
three
times
under

no
load

and
make

sure
that

specified
CO

per

centage
is
obtained

I
1
Remove

cap
and
connect
air

hose
to
air
check
valve

If

idling

speed
increases

readjust
it

to

specified
speed
with
throttle
ad

justing
screw

12
Warm

up
engine
for
about
four

minutes
at
2
000

rpm
under
n
load

13
Measure

CO

percentage
at

idling

speed
After

step
12
has
been
com

pleted
wait

for
one
minute
before

making
CO

percentage
measurement

14

If
CO

percentage
measured
in

step
13
is
less
than
0
3
the

catalylic

converter
is

normal

15
If
CO

percentage
measured
in

step
13
is

over
0
3
recheck
A
I
S

and

replace
air

check
valve
Then

perform
inspection
steps
12

and
13

16
If
CO

percentage
is
still

over

0
3
in

step
15

catalytic
converter
is

malfunctioning
Replace
catalytic
con

verter

CHECKING
FLOOR

TEMPERATURE

WARNING
SYSTEM

INSPECTION

Floor

warning
temperature

system

Apply
parldng
brake
Shift

gears

into
Neutral
for

manual
transmission

and
Neutral
or
Park
for
automatic

transmission

1

Ensure
that
floor
tern

perature

warning

lamp
lights
when

ignition

switch
is

turned
to
the
S

position

If
not
check

lamp
for
burned

bul
bs

ENGINE

LUBRICATION
SYSTEM

SERVICE
DATA
AND

SPECIFICATIONS

Oil

pump

Standard
Wear
limit

mm
in
0
04
to

0
08

0
0016
to
0
0032

less
than
0
12
0
0047

0
15
toO
21

0
0059
to
0

0083
0
20

0

0079

0
20

0
0079

0
5

0

0197
Rotor
side
clearance

rotor
to
bottom
cover

Rotor

tip
clearance
mm
in

Outer
rotor
to

body
clearance
mm
in

Oil

pressure
regulator
valve

Oil

pressure
at

idling

Regulator
valve

spring

Free

length

Pressured

length

Regulator
valve

opening

pressure
kg
cm2

psi
0

8
to
2
8

II
to
40

mm
in

mmOn

kg
em2

psi
52
5
2
067

34
8
1
370

3
5
to
5

0
50
to

71

Tightening
torque

Oil

pump
bolt

Oil

pump
cover
bolt

Regulator
valve

cap
nut
kg
m
ft
lb

kg
m
ft
lb

kg
m
ft

Ib
1
1
to
1
5
8
0

to
10
8

0

7
to
1

0
5
1

to
7
2

4
to
5
29

to
36

TROUBLE
DIAGNOSES
AND
CORRECTIONS

Condition
Probable
causes
Corrective
actions

Oil

leakage
Damaged
or
cracked

body
cover

Oil

leakage
from
gasket

Oil

leakage
from

regulator
valve

Oil

leakage
from
blind

plug
Replace

Replace

Tighten
or

replace

Replace

Decreased
oil

pressure
Leak
of
oil
in

engine
oil

pan

Dirty
oil
strainer

Damaged
or
worn

pump
rotors

Faulty
regulator

Use
of

poor
quality
engine
oiL
Correct

Clean
or

replace

Replace

Replace

Replace

Warning

light

remains
on

engine
running
Decreased
oil

pressure

Oil

pressure
switch
unserviceable

Electrical
fault
Previously
mentioned

Replace

Check
circuit

Noise
Excessive
backlash
in

pump
rotors

Replace

EL
5

j

EC231

Thermal

vacuum
valva
o

o

m
Emission

Control

System

0

o

o

o

l

l
@

The
thermal
vacuum
valve

is

mounted
in

the

engine
thermostat

housing
It

detects

engine
coolan
t

tem

perature
by
means
of
a

built
in

bi

metal
and

opensor
closes
the

vacuum

passage
in
the

thermal
vacuum

valve

mt

li

t

00
t

EC232

Fig
EC
54
Thennal

vacuum
valve
To
E

G
R
control
valve

From
carburetor

1

Spring

2
Bi
metal

3

O

ring

E
G
R

warning

system

The

E
G
R

warning
system
install
1

Diaphragm
spring

2

Diaphragm

3
Valve
shaft

4

Valve

5
Valve

Seat

6
Valve
cham
ber

Fig
EC
53
E
G

R
control
value

When
the

vacuum

passage
is

open
the

carburetor
suction

vacuum
is

applied

to
the

diaphragm
of
the
E
G
R

con

trol
valve
to

actuate
the

taper
valve

connected
to
the

diaphragm

theconsiiiictlo

nlie
thermal

vacuum
valve
is

shown
below

ed

independently
of
the

E
G
R

con

trol

system
monitors

the
distance
the

car
has
travelled
and

indicates
when

EC
22
the
E

G
R

control

system
must
be

checked

The
E
G
R

warning
system
consists

of

an
odometer
switch

detector
drive

counter
E

G
R

warning

lamp
and

harnesses

When
the

earn
in
the

odom

eter
switch
connected
to

the

speed

ometer
turns

once
for

each
OAkm
4

mile
the

contact

point
of
the
elec

trica
circuit
closes

allowing
electric

current
to
flow

through
the

magnet

coil
of

the
detector

drive
counter

Thus

energized
the

magnet
coil
ac

Wates

the
latchet
to

turn
the
c
unter

wheel

by
one

pitch
When
the

number

of

counts
reaches
50
000
the
latchet

drops
in

a

groove
provided
on
the

periphery
of

the
counter
wheel
to

activate

the
detector

drive
counter

switch

Then
the

E
G
R

warning

lamp

comes
on

indicating
that
the
E
G
R

control

system
Should
be
checked

The

detector
drive

coun
teT
is

equip

ped
with
an
odometer
which

can
tell

when
to
service

the
E

G
R
contr0
I

system

After

completing

periodic
check

reset
the
odometer
to

zero
by
hand

proceeding
as
follows

1
Remove

grommet
installed
on

the
side

surface
of

detector
drive

counter
unit

2
insert

a
bar

or
a
screwdriver

tip

into
the

hole
from

which

grommet
has

been

removed
and

press
down
knob

provided
in

the
detector
drive
counter

for

resetting

The
E

G
R

warning

lamp
comes

on

under
the

following
circumstances

1
When
the
number
of

counts
has

reached
50
000
In
this

case
the

lamp

indicates
that
E

G
R

control

system

must
be
checked

2
When

operating
starter
motor

Notes

a
It
is

an
indication
of

problem
in

the

E

G
R

warning
lamp
or

problems

in
the

point
or
in
the
harnesses
if

the

lamp
does
not

light
at

50
000

counts

b

The
E

G
R

warning
system
is

mounted

on
all
620
models

except

those

bound
for
California
and

Canada

4
E
G
R

warning
system

EC251

Detector
drive
counter

Detecfor
drive
counter
is
secured

on
the

top
of
R
H

hoodledge
panel
in

engine
room
To

remove
detector
drive

counter
disconnect
w
COJUlector

and

loosen
two
bolts

securing
detector

drive
counter
to
hoodledge

panel

2

E
G
R

warning
lamp

E
G
R

warning
lamp
is
mounted
at

the

top
cen
ter
of
instrument

pad
To

remove
E
G

R

warning
lamp
proceed

as
follows

1
Remove

masking
panel

On
models

equipped
with
radio

remove

warning
lamp
from
under
in

strument

panel

2

E
G
R

warning
lamp
is

a
twist

type

Remove

lamp
and
socket

as
an

assembly
Push
and
twist

lamp
off

can

EC554

Fig
EC
60
Removing
E
G
R

warning

lamp
Emission
Control

System

3
Odometer
switch

Odometer
switch
is
mounted
on
the

back
side
of

speedometer
Cam
in
the

odometer
switch
is
rotated

by
the

speedometer
To

dismount
odometer

switch

proceed
as
follows

I

Dismount
combination
meter
as

sembly

2
Remove
meter
front
cover
and

take
off

clips
and
screws
to

dismount

shadow

plate

3

Loosen
screws

securing
speed

ometer
to

printed
circuit

housing
then

remove

speedometer

4

Remove
two
screws

securing

odomete
switch
to
the

back
side
of

speedometer
and
detach
odometer

switch

EC239

Fig
EC
61

Removing
odometer

switch

InstaUatlon

To
install
reverse
the
removal

pro

cedure

EC24
V

r
CID

1
Detector
drive
counter

2
E
G
R
warning
lamp

3
Speedometer

Fig
EC
59
E
G
R

warning
y
tem

INSPECTION

Checking
E

G
R
control

system
in

its
mounted
conditionS

I

Make
a

thorough
visual
check
of

E

G
R
control

system
If

necessary

wipe
away
oil
to

facilitate

inspection

If

any
hoses
are
cracked
or

broken

replace

2

With

engine
running
check

E

G
R

warning
system
for

proper

function
Make
sure
that
E

G
R
warn

ing
lamp
lights
when

ignition
switch
is

turned

to
START

position
starter

mo

tor
runs
If
E
G
R

wanung
lamp
does

not

light
inspect
harnesses
and

con

nectors
or

replace
warning
lamp
Then

turn

ignition
switch
to
ON

position

and

check
the
following
items

I

If
odometer
of
detector
drive

counter
has
not
reached
50
000

counts
make
sure
that
E
G
R

warning

lamp
does
not
light

2
If
odomete
of
detector
drive

counter
has
attained
50
000
counts

make
sure
that
E
G
R

warning
lamp

lights

If

warning
lamp
does
not

light

check
harnesses
connectors
and
de

tector
drive
counter
replace
warning

lamp
or
detector
drive
counter
if

necessary

Notes

Operation
oC
E
G
R

warning
lamp

is
as
Collows

REMOVAL

AND

INSPECTION

Removal
and

inspection
can
be

done

as
follows

Removal

Catalytic
converter

1

Apply
parking
brake

2

Place
wheel
lock
under
each
tire

3

Jack

up
the
vehicle

4
Remove
lower
shelter
of

catalytic

converter

5
Dismount

catalytic
converter

EC453

Fig
EC
69
Removing

catalytic

conuerter

Inspection

Preliminary
inspection

Visually
check
condition
of
all

component
parts
including

ho
s

tubes
and
wires

replace
if

necessary

Refer
to

Inspection
of
A
I
S
on

page
EC
17

Catalytic
converter

Whether

catalytic
converter
is
nor

mal
or
not
can
be
checked
by
ob

serving
variation
in

CO

percentage

The

checking

procedure
is

as
follows

Apply
parking
brake
Shift

gears

into
Neutral
for
manual
transmission

and
Neutral
or
Park
for
automatic

transmission

1

Visually
check

catalytic
converter

for

damage
or
cracks
Emission
Control

System

2
Remove
air
hose
between

5

way

connector
and
air
check
valve

Plug
the

disconnected
hose
to

prevent
dust

from

entering
Refer
to

page
ET
12

3

Check
carburetor

pipes
for

proper

connection

4

Warm

up
engine
sufficiently

5

Race

engine
1

500
to
2
000

rpm

two
or
three
times

under
no
load
then

run

engine
for
o
e
minute
at

idling

speed

6

Adjust
throttle

adjusting
screw

until

engine
attains
to

specified
speed

Refer
to

page
ET
10

7
Check

ignition
timing
If
neces

sary
adjust
it
to

specifkations
Refer

to

page
ET
10

B

Adjust
idle

adjusting
screw
until

specified
CO

percentage
is

obtained

Refer
to

page
ET
12

9

Repeat
the

adju
stment

process
as

described
in

steps
5
to
8
above

until

specified
CO

percentage
is
obtained

Note

Adjustment
in

step
9
should
be

made
ten

minutes
after

engine
has

wanned

up

10
Race

engine

1
500
to
2
000

rpm
two
or
three
times

under
no
load

and
make
sure
that

specified
CO

per

centage
is
obtained

11
Remove

cap
and
connect
air

hose
to

air
check
valve

If

idling

speed
increases

readjust
it

to

specified
speed
with
throttle
ad

justing
screw

12
WaRn

up
engine
for

about
four

minutes
at
2
000

rpm
under
no
load

13
Measure
CO

percentage
at

idling

speed
After

step
12
has
been
coin

pleted
wait

for
one
minute
before

making
CO

percentage
measurement

14
If
CO

percentage
measured
in

step
13
is
less
than
0
3

the

catalytic

converter

is
normal

15
If
CO

percentage
measured
in

step
13
is
over
0
3

recheck
A
I
S

and

replace
air
check
valve
Then

perform
inspection
steps
12
and
13

EC
27
16
If
CO

percentage
is

still
over

0
3
in

step
15

catalytic
conyerter
is

malfunctioning
Replace
catalytic
con

verter

INSTALLATION

To
install

reverse
the
removal

pro

cedure

Bolt

lightening

torque

specifications

Tightening

torque

Catalytic
converter

2
6
to
3
4

kg
m

19
to
25
ft
Ib

FLOOR

TEMPERATURE

WARNING
SYSTEM

DESCRIPTION

The
floor

temperature
warning

system
consists
of
a
floor

temperature

sensing
switch
installed

on
the
vehi

cle
s
floor
floor

temperature
relay
and

a

warning

lamp
on
the
instrument

panel
and
wires
that
connect
these

parts

When
the
floor

tempera
ture
rises
to

an
abnormal
level
the

warning
lamp

will

light
to
call
the
attention
of
the

driver
The

wiring
diagram
of
this

system
and
location
of
the

floor

temperature
sensing
switch
are
ilIus

trated
in

Figures
EC
70
and
EC
71

Floor
temparature
warning

lamp

Refer

to

Figure
EC
74

for
the

loca

tion
of
this

part

L

1t

1

RAt

Fig
EC
74
Location
of
floor

temperature
warning
lamp

INSTALLATION

To
install
reverse
the
order
of

rem
ovaL

INSPECTION

Floor
warning
temperature

system

Apply
parking
brake
Shift

gears

into
Neutral
foI
manual
transmission

and
Neutral
or
Park
for
automatic

transmission

1
Ensure
that
floor

temperature

warning

lamp
lights
when

ignition

switch
is
iumed

to
the
S

position

If

not
check

lamp
for
burned

bulbs

Replace
bulb
if
bulb
is
burned
out

If

bulb
is

not
burned
trace
wire
s

back
to

ignition
switch

Repair
or

replace
if

necessary

2
Be

sure
that
floor

temperature
is

cool
below
800C

1760Fj
before

carrying
out
the

following
procedure

I
Remove
rearseat

2

Ignition
switch
is

turned
to
the

IG

position

3
Ensure
that
floor

temperature

warning
lamp
goes
out

4
Heat

surrounding
areas
of
floor

temperature
sensing
switch
with
a

proper
heater
to
ensure
that
floor

temperature
warning
lamp
glows
when

floor
is
heated

to
the

specifications
as

shown
in
the
table
below
Emission
Control

System

Temperature

sensing
switch

Contact
close
Temperature

warning
lamp

Off

Contact
open
On

Note

Avoid

heating
floor

tempera

ture

sensing
switch

directly

If

lamp
does

not
glow
check
floor

temperature
sensing
switch
connector

for

continuity
with

a
circuit
tester

If

continuity
should
exist
after

heated

surrounding
areas
of
floor
tem

perature
sensing
switch

replace
tem

perature
sensing
switch

If
con

tinuity
does

not
exist

trace

the

wiring
back
to

relay
or
check
the

following
step
3

Repair
or

replace

wire
s
if

necessary

Note
The

floor

temperature
sensing

switch

may
be
heated

through
the

floor

by
a

proper
heater

3
Turn

ignition
switch
to
the

IG

position
and
disconnect
floor

temper

ature

sensing
connector
The

lamp

should
remain

on
If

not
check
floor

temperature
relay
for

continuity
with

2
00

r
I

141

J

To
floor

temperatwe

warning
lamp

2
From

S

position

3
From

IG

position

4

From

ignition
switch

5
To
floor

temperature

sensing
switch
O

When
floor

temperature

warning
lamp
lights

Check
floor

temperature
warning

lamp

1

Open
or

shorj
circuit
in

wiring

harness

2

Check
fuel

system
with

regard
to

the

following
items

Refer
to

Inspec

lion
of
Fuel

System

EC
29
Floor

temperature

Below
1050C
221
OF

Above

1050C
221
OF

a
circuit

tester

Referring
to
the

following
floor

temperature
relay
if

relay
is
normal

trace
wire
s

back
to

ignition
switch

Repair
faulty
wiring

Floor

temperature
relay

When

checking
floor

temperature

relay
for
unit

remove
it
and

proceed

as
follows

1

Check
for

continuity
between

@

and

ID
Continuity
should
exist

Check
for

continuity
between

CD

and@
Continuity
should
exist

Check
for

continuity
between

CD

and

@
Continuity
should
not

exist

2

Apply
a
12

volt
doc
across

@
and

ID
to

ensure
that

continuity
exists

between

CD
and

@
and
that

con
ti

nuity
does

not
between

CD
and

@
If

test
results
dn

not

satisfy
the
above

replace
the

floor

temperature
relay

EC344

Fig
EC
75

Checking
floor
temperature
relay

1
Float
level

2
Choke

3

Normal
fuel

supply
system
Prima

ry
and

secondary

4
Accelerator

pump

5
Power
valve

6
B
C
D
D

7
Fuel
strainer

8
Air
cleaner

Condition
Engine
Electrical

System

Probable
cause

Starting
motor

cranks

slowly
Dirty
or
worn
commutator

Armature
rubs

field
coil

Damaged
solenoid
switch

Starting
motor

operates
but
does

not
crank

engine
Worn

pinion

Locked

pinion
guide

Worn

ring

gear

Starting
motor
will

not

disengage
even
if

ignition
switch
is

turned
off
Damaged
solenoid
switch

Damaged

gear
teeth

The

charging
circuit
consists

of
the

battery
alternator

regulator
and

necessary

wiring
to
connect
these

parts
The

purpose
of
this

system
is
to

convert
mechanical

energy
from
the

engine
into

electrical

energy
which

is

used
to

operate
all

electrically

operat

ed
units

and
to

keep
the

battery
fully

charged

When
the

ignition
switch
is

set
to

ON
current
flows
from
the

battery

to

ground
through
the

ignition
switch

voltage
regulator
IG
terminal

primary

side
contact

point
PI

movable

contact

point
P2

voltage

regulator

IF

terminal
alternator
IF
terminal

rotor

field
coil
and
alternator

E

terminal

as
shown
in

Figure
EE

23

by

full
line

arrow
marks
Then
the

rotor

in

the

alternator
is
excited

On
the

other
hand

current
flows

from
the

battery
to

ground

through
the

ignition

switch

warning

lamp
voltage
regula

tor
L

terminal

lamp
side
contact

point
P4

movable

contact

point

P5
and

voltage
regulator
E
termi

nal
as
shown

by
dotted

line
arrow
CHARGING
CIRCUIT

marks
Then

the

warning
lamp
lights

When
the
alternator

begins
to

op

erate
three

phase

alternating
current
is

induced
in

the

stator
armature
coil

This

alternating
current
is
rectified

by

the

positive
and

negative
silicon

diodes
The
rectified

direct
current

output
reaches
the
alternator
A

and

E

terminals

On
the
other
hand
the
neutral

point
voltage
reaches
N
and
E

terminals

nearly
a
half
of

the

output

voltage
and
current
flows
from

voltage
regulator
N
terminal
to
E

terminal
or

ground
through
the
coil

VCI
as
shown
in

Figure
EE
24

by

the
dotted
line
arrow
marks
Then
the

coil
VCI
is
excited
and
the

movable
contact

point
IPS
comes

into
contact
with

voltage
winding
side

contact

point
P6
This
action
causes

to
turn
off

the

warning
lamp
and

complete
the

voltage
winding
circuit

as
shown

by
the
full

line
arrow
marks

When
the
alternator

speed
is
in

creased
or
the

voltage
starts
to
rise

excessively
the
movable
contact

point

EE
12
Corrective
action

Clean
and

repair

Replace
assembly

Repair
or

replace

Replace

Repair

Replace

Repair
or

replace

Replace
damaged

gear

P2
is

separated
from

the

primary

side
contact
PI

by
the

magnetic

force

of
coil
VC2
Therefore

registor
RI
is

applied
into
the
rotor

circuit

and

output
voltage
is
decreased

AJ

the

output
voltage
is
decreased

the

movable
contact

point
P2
and

primary
side
contact
Pin

comes
into

contact
once

again
and

the
alternator

voltage
increases

Thus
the

rapid

vibration
of
the
movable

contact

point

IPl

maintains
an
alternator

output

voltage
constant

When
the
alternator

speed
is

further

increased
or
the

voltage
starts
to
rise

excessively
the

movable
contact

point

P2
comes

into
contact
with

secondllJ
side
contact

point
P3

Then
the
rotor
current
is

shut
off
and

alternator

output
voltage
is

decreased

immediately
This

action
causes

movable
contact
n
to

separate

from

secondary
contact
P3
Thus

the

rapid
vibration
of

the
movable

contact

point
P2

or

breaking
and

completing
the

rotor
circuit
maintains

an
alternator

output
voltage
constant