Isuzu N-Series. Manual - part 1024

CAB AND CHASSIS ELECTRICAL 8-201

H-5

J-5

P-1

(12 V)

P-2

P-1

(24 V)

P-4

P-2

(24 V)

P-3

P-5

(12 V)

No.

Connector Face

001-018

1

000-003

000-004

000-004

000-004

000-006

000-006

000-007

P-5

(24 V)

R-1

R-1

R-6

R-6

No.

Connector Face

000-002

006-004

1

2

3

4

5

6

006-005

3

2

1

6

5

4

006-004

1

2

3

4

5

6

006-005

3

2

1

6

5

4

1

2

3

7

8

9

13

14 15

19

20 21

25

26 27

31

32 33

34

35

36

37

4

5

6

10

11 12

16

17 18

22

23 24

28

29 30

38

39 40

6

5

4

12

11 10

18

17 16

24

23 22

30

29 28

40

39 38

3

2

1

9

8

7

15

14 13

21

20 19

27

26 25

33

32 31

34

35

36

37

N8A5488E

8-202 CAB AND CHASSIS ELECTRICAL

H-6

Diagnosis

Quick Chart for Check Point
1. Horn

Notice:
Figure in parenthesis “( )” indicates the order of inspection.

2. Backup Light

Notice:
Figure in parenthesis “( )” indicates the order of inspection.

1

2

1

2

1 2 3 4

5 6 7 8

9 10 11 12 13

14 15 16 17 18

2

1

2

1

4 3 2 1

8 7 6 5

13 12 11 10 9

18 17 16 15 14

H - 6

H - 7

H - 8

N8A5489E

Check point

Fuse

F-19, F-20 

(15 A)

Horn

Horn SW

Horn 
relay

Horn 

contact

Cable 

harness

Trouble
mode

1-1. Horn does not sound

❍

(1)

❍

(4)

❍

(6)

❍

(2)

❍

(5)

❍

(3)

1-2. Horn does not shut off

❍

(2)

❍

(1)

❍

(3)

Check point

Fuse

F-16 (10 A)

Backup light 

SW

(Inhibitor SW)

Backup 

light bulb

Backup 

buzzer

Cable 

harness

Trouble
mode

2-1. Both backup lights inoperative

❍

(1)

❍

(3)

❍

(2)

2-2. Backup light on the left (or right) 
side inoperative

❍

(1)

❍

(2)

2-3. Backup light remains on

❍

(1)

CAB AND CHASSIS ELECTRICAL 8-203

1. Horn
1-1. Horn Does Not Sound

• IS FUSE  F-19  ,  F-20   (15A) NORMAL?

YES

NO

REPLACE THE FUSE

• IS THE HORN RELAY NORMAL?

• IS THE HORN NORMALLY GROUNDED?

YES

NO

REPLACE THE HORN RELAY

• IS THE HORN CONNECTOR 1  J-4  OR 1  J-5

SECURELY CONNECTED?

YES

NO

CLEAN UP THE FITTING SURFACE AND THE
GROUND FIRMLY

• DISCONNECT THE HORN SWITCH CONNECTOR

• IS THERE BATTERY VOLTAGE APPLIED BETWEEN 

3  B-70  AND THE GROUND?

YES

NO

CONNECT THE CONNECTOR SECURELY

• IS THERE ANY CONTINUITY BETWEEN THE HORN

RELAY HARNESS SIDE CONNECTORS 5  X-2  AND 
1  J-4  (OR 1  J-5  )?

YES

NO

REPAIR A POOR CONNECTION AT THE
CONNECTORS OR AN OPEN CIRCUIT OR REPAIR
A POOR CONNECTION AT THE HORN
CONNECTOR

YES

NO

  DOES THE HORN SOUND WHEN CONNECTING THE

BATTERY (+) TERMINAL TO THE HORN CONNECTOR 
1  J-4  (1  J-5  ), AND (-) TERMINAL TO THE HORN
BRACKET?

NO

REPAIR A POOR CONNECTION AT THE
CONNECTORS OR AN OPEN CIRCUIT IN THE
CIRCUIT

PEPLACE THE HORN

N8A0187E

8-204 CAB AND CHASSIS ELECTRICAL

1-2. Horn Does Not Shut Off

2. Backup Light
2-1. Backup Lights Inoperative

• IS THE HORN RELAY NORMAL?

• REMOVE THE HORN SW

• IS THE MOVABLE PORTION OF THE HORN SW

ALWAYS OUT OF CONTACT WITH THE GROUND
BRACKET?

YES

NO

REPLACE THE HORN RELAY

REPAIR A SHORT CIRCUIT BETWEEN HORN RELAY
HARNESS SIDE CONNECTORS 4  X-2  AND 3  B-70 

YES

NO

REPAIR OR REPLACE THE HORN SW

N8A0188E

• IS FUSE  F-16  (10A) NORMAL?

• IS  J-9  SECURELY GROUNDED?

YES

NO

REPLACE THE FUSE

• TURN THE STARTER SW ON

• IS THE BATTERY VOLTAGE APPLIED BETWEEN THE

BACKUP LIGHT SWITCH HARNESS SIDE CONNECTOR
1  E-10  (OR 1  J-49  )AND THE GROUND?

YES

NO

GROUND IT SECURELY

• ENTER THE TRANSMISSION SHIFT LEVER TO

REVERSE POSITION 

• WHEN REMOVE THE CONNECTOR OF THE BACKUP

LIGHT SWITCH, IS THERE ANY CONTINUITY 
BETWEEN THE SW SIDE CONNECTORS 1  E-10  AND 
2  E-10  (OR 1  J-49  AND 2  J-49  )?

YES

NO

REPAIR A POOR CONNECTION AT THE
CONNECTORS OR AN OPEN CIRCUIT BETWEEN
FUSE  F-16  (10A) AND 1  E-10  OR 1  J-49  

REPAIR A POOR CONNECTION AT THE CONNECTORS 
OR AN OPEN CIRCUIT BETWEEN THE BACKUP LIGHT
SWITCH HARNESS SIDE CONNECTORS 2  E-10  
(OR 2  J-49  )AND 4  H-16

YES

NO

REPAIR OR REPLACE THE BACKUP LIGHT
SWITCH OR INHIBITOR SW

N8A0189E