Isuzu Trooper (1998-2002 year). Manual - part 901

8D–138

WIRING SYSTEM

1–5.   Both Headlights In High-Beam Inoperative

•

DISCONNECT THE DIMMER•
PASSING SW CONNECTOR (COMBINATION SW)

YES

REPAIR A POOR CONNECTION AT THE CONNECTORS
OR AN OPEN CIRCUIT BETWEEN
15   B-12    AND 16   H-16

REPAIR OR REPLACE THE DIMMER•
PASSING SW

NO

•

WITH THE SWITCH AT HIGH-BEAM, IS THERE
CONTINUITY BETWEEN THE SWITCH CONNECTOR TERMINALS
15   B-12    AND 16   B-12    ?

1–6.   Headlight High-Beam On The Left (Or Right) Side Inoperative

•

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

YES

•

IS THE FUSE F–4 (15A) (OR F–5 (15A))
NORMAL?

YES

REPLACE THE BULB

NO

•

DISCONNECT THE DIMMER·PASSING SW CONNECTOR

•

WITH THE SWITCH AT THE HIGH–BEAM POSITION, IS THERE 
CONTINUITY BETWEEN 15   B–12   AND 16   B–12   ?

YES

REPLACE THE FUSE

NO

REPAIR A POOR CONNECTION AT THE CONNECTORS
OR AN OPEN CIRCUIT BETWEEN 3   C–21   AND F–4 
(15A) (OR 3   C–32    AND F–5 (15A))

NO

REPAIR OR REPLACE THE DIMMER·PASSING SW

REPAIR  A POOR CONNECTION AT THE CONNECTORS OR AN
OPEN CIRCUIT BETWEEN 15   B–12   AND 2   C–21   (OR 15   B–12
AND 2   C–32   )

•

IS THE CONTINUITY BETWEEN
3    C–21   AND F–4 (15A) (OR 3   C–32  
AND F–5 (15A)) NORMAL?

NO

YES

WIRING SYSTEM

8D–139

1-7.   Headlight Beam Does Not Change

1-8.   Headlights Remain On When The Lighting SW Is Turned Off

YES

•

DISCONNECT THE DIMMER•PASSING
SW

REPAIR OR REPLACE THE DIMMER•PASSING SW

NO

•

DOES THE LEVER OF THE DIMMER•
PASSING SW OPERATE SMOOTHLY AND SECURELY?

•

WITH THE SWITCH AT THE LOW-BEAM POSITION, IS
THERE CONTINUITY BETWEEN 13   B-12   AND 16   B-12    ?
ALSO, WITH IT AT THE HIGH-BEAM POSITION, IS THERE
CONTINUITY BETWEEN 15    B-12   AND 16    B-12    ? 

NO

REPAIR OR REPLACE THE DIMMER•PASSING SW

YES

•

REPLACE THE LIGHTING RELAY

NO

•

IS THE LIGHTING RELAY NORMAL?

REPAIR OR REPLACE THE LIGHTING SW

NO

DISCONNECT THE LIGHTING SW CONNECTOR

•

IS THE CONTINUITY BETWEEN
THE SWITCH CONNECTOR TERMINALS 1   B-12    AND
7   B-12    NORMAL?

YES

REPAIR A SHORT CIRCUIT BETWEEN
5      X-1    AND 1    B-12    

8D–140

WIRING SYSTEM

REPAIR OR REPLACE THE LIGHTING SW

1-10.   Passing Lights Inoperative

•

DISCONNECT THE DIMMER•PASSING SW CONNECTOR

YES

REPAIR A POOR CONNECTION AT THE CONNECTORS
OR AN OPEN CIRCUIT BETWEEN 5   H-15    AND
14   B-12 

REPAIR OR REPLACE THE SWITCH

NO

•

WITH THE SWITCH AT PASSING POSITION, IS THERE
CONTINUITY BETWEEN THE SWITCH CONNECTOR TERMINALS
14   B-12    AND 16   B-12    , AND 15    B-12   AND 16   B-12   ?

1-9.   Headlights Come On With The Lighting SW At The Clearance Light Position

WIRING SYSTEM

8D–141

2-1.   Both Headlights Inoperative

•

IS THE LIGHTING RELAY NORMAL?

YES

 REPLACE THE RELAY

NO

•

IS   B-19   GROUNDED SECURELY?

YES

NO

GROUND IT SECURELY

•

IS THE DIODE NORMAL ?

YES

NO

REPLACE THE DIODE

•

IS THE DIMMER RELAY NORMAL?

YES

NO

REPLACE THE RELAY

•
•

DISCONNECT THE LIGHTING SW CONNECTOR

YES

NO

•
•

REMOVE THE LIGHTING SW

YES

NO

REPAIR A POOR CONNECTION AT THE CONNECTORS
OR AN OPEN CIRCUIT BETWEEN THE FUSIBLE LINK
 FL-1 (80A) AND 1   B-12

REPAIR OR REPLACE THE LIGHTING SW

REPAIR A POOR CONNECTION AT THE CONNECTORS OR
AN OPEN CIRCUIT BETWEEN THE LIGHTING SW HARNESS SIDE 
CONNECTOR 7    B-12    AND   B-19

IS THE BATTERY VOLTAGE APPLIED BETWEEN THE 
HARNESS SIDE CONNECTOR 1   B-12   AND GROUND?

IS THERE CONTINUITY BETWEEN 1   B-12   AND  7   B-12   WHEN
SETTING THE LIGHTING SW AT THE HEADLIGHT POSITION?