Isuzu Trooper (1998-2002 year). Manual - part 921

8D–218

WIRING SYSTEM

DIAGNOSIS

Quick Chart for Check Points

Check point

Fuse

C-14 (15A)

Cable

harness

1

Both stoplights inoperative

Trouble mode

2

Stoplight on the left (or right) side inoperative

Stoplight

SW or 

brake SW

Stoplight

bulb

High mounted stoplight inoperative

3

High mount

stoplight

ASM

WIRING SYSTEM

8D–219

1

Both Stoplights Inoperative

•

IS THE BATTERY VOLTAGE APPLIED TO 1   B-14   (1   B-13   )
OF THE STOPLIGHT SW (OR THE BRAKE SW)?

YES

YES

REPLACE THE FUSE

NO

REPAIR A POOR CONNECTION AT THE CONNECTORS
OR AN OPEN CIRCUIT BETWEEN THE FUSE C-14 (15A)
AND 1   B-14    (1   B-13   )

NO

•

IS FUSE C-14 (15A) NORMAL?

•

IS    R-4     GROUNDED SECURELY?

GROUND IT SECURELY

YES

NO

•

REMOVE THE STOPLIGHT SW (OR THE BRAKE SW) CONNECTOR.

•

WHEN DEPRESS THE BRAKE PEDAL, IS THERE ANY 
CONTINUITY BETWEEN THE 1   B-14   AND 2   B-14  
 (OR 1   B-13    AND 4   B-13    ) OF THE SWITCH?

DOES THE PUSH ROD OF THE STOPLIGHT SW (OR THE
BRAKE SW ) OPERATE SMOOTHLY?

YES

NO

•

REPLACE THE STOPLIGHT SW (OR BRAKE SW)

REPAIR A POOR CONNECTION AT THE CONNECTORS OR AN
OPEN CIRCUIT BETWEEN 2   B-14   (4   B-13   ) AND 7  H-32

YES

NO

REPLACE THE STOPLIGHT SW (OR BRAKE SW)

8D–220

WIRING SYSTEM

2

Stoplight On The Left (Or Right) Side Inoperative

(Body Build-in Type Stoplight)

(Bumper Build-in Type Stoplight)

•

WITH THE STOPLIGHT SW OR BRAKE SW DEPRESSED, IS THE
BATTERY VOLTAGE APPLIED BETWEEN 5    R-13    (OR 5    R-12   )
AND THE GROUND?

YES

REPAIR A POOR CONNECTION AT THE CONNECTORS 
OR AN OPEN CIRCUIT BETWEEN 7    H-32    AND
5    R-13    (OR 5    R-12    )

NO

•

IS THE STOPLIGHT BULB ON THE LEFT (OR RIGHT) SIDE NORMAL?

REPLACE THE BULB

YES

NO

REPAIR A POOR CONNECTION AT THE CONNECTORS OR AN 
OPEN CIRCUIT BETWEEN 1   R-13    (1    R-12   )  AND     R-4

•

WITH THE STOPLIGHT SW OR BRAKE SW DEPRESSED, IS THE
BATTERY VOLTAGE APPLIED BETWEEN 3    F-7    (OR 3    F-8    )
AND THE GROUND?

YES

REPAIR A POOR CONNECTION AT THE CONNECTORS 
OR AN OPEN CIRCUIT BETWEEN 7   H-32    AND
3    F-7    (OR 3   F-8    )

NO

•

IS THE STOPLIGHT BULB ON THE LEFT (OR RIGHT) SIDE NORMAL?

REPLACE THE BULB

YES

NO

REPAIR A POOR CONNECTION AT THE CONNECTORS OR AN 
OPEN CIRCUIT BETWEEN 2   F-7    (2    F-8   )  AND     R-4

WIRING SYSTEM

8D–221

3

High Mounted Stoplight Inoperative

•

•

REPAIR A POOR CONNECTION AT THE CONNECTORS OR AN
OPEN CIRCUIT BETWEEN 2    G-9    AND    R-3 

ROMOVE THE HIGH MOUNTED STOPLIGHT CONNECTOR 
IS THERE ANY CONTINUITY BETWEEN THE HIGH MOUNTED 
STOPLIGHT CONNECTOR 1   G-9      AND 2   G-9    ?

YES

NO

GROUND IT SECURELY

YES

NO

REPAIR OR REPLACE THE HIGH MOUNTED
STOPLIGHT

•

YES

NO

REPAIR A POOR CONNECTION AT THE CONNECTORS 
OR AN OPEN CIRCUIT BETWEEN 1     G-9     AND 
1    H-37

•

IS     R-3     SECURELY GROUNDED?

IS THE BATTERY VOLTAGE APPLIED BETWEEN 1    G-9     
AND THE GROUND WHEN THE BRAKE PEDAL IS
DEPRESSED?