1998 ISUZU TROOPER lights

8DÐ134 WIRING SYSTEM
Diagnosis
Quick Chart for Check Points
1. Headlight (RHD)
Check point
Trouble modeFuse
F–4
(15A)F–5
(15A)Lighting
relayLighting
SWDimmer•
Passing
SWCable
harness Headlight
bulb
1–1. Both Headlights inoperative
1–2. Headlight on the left (or
right) side inoperative
1–3. Both headlights in
low-beam inoperative
1–4. Headlight low-beam on
the left (or right) side
inoperative
1–5. Both headlights in
high–beam inoperative
1–6. Headlight high-beam on the
left (or right) side
inoperative
1–7. Headlight beam does not
change
LH RH
1–8. Headlights remain on when
the lighting SW is turned off
1–9. Headlights come on with
the lighting SW at the
clearance light position
1–10. Passing lights inoperative

WIRING SYSTEM 8DÐ135
Check point
Trouble modeFuse
F–4
(10A)F–5
(10A)Dimmer
relayLighting
SWDimmer•
Passing
SWCable
harness Headlight
bulb
2–1. Both Headlights
inoperative
2–2. Headlight on the
left (or right) side
inoperative
2–3. Both headlights
in low-beam
inoperative
2–4. Headlight low-
beam on the left
(or right)
side inoperative
2–5. Both headlights
in high-beam
inoperative
2–6. Headlight
high-beam on
the left (or right)
side inoperative
2–7. Headlight beam
does not change
Lighting
relayF–6
(10A)F–7
(10A)
2–8. Headlights
remain
on when the
lighting SW is
turned off
2–9. Headlights come
on with the
lighting SW at
the clearance
light position
Diode
2–10. Passing lights
inoperative
LH
RH
2. Headlight (LHD)

8DÐ136 WIRING SYSTEM
Check point
Trouble modeFuse
F–8
(15A or 20A)Cable
harness Fog light
bulb
3–1. Both FRT fog lights
inoperative
(while the clearance light is ON)
3–2. FRT fog light on the left
(or rigth) side inoperative
(while the clearance light is ON)
LHRH
FRT
fog light
SWFRT
fog light
relayRR
fog light
SWRR
fog light
relay
3. FRT fog lights

WIRING SYSTEM 8DÐ137
1-1. Both Headlights Inoperative
·IS THE LIGHTING RELAY NORMAL?
YES
·IS B-19 GROUNDED SECURELY?
YES
REPLACE THE LIGTHING RELAY
NO
·DISCONNECT THE LIGTHING SW CONNECTOR
·IS THE BATTERY VOLTAGE APPLIED BETWEEN THE HARNESS
SIDE CONNECTOR 1 B-12 AND GROUND?
YES
GROUND IT SECURELY
NO
·REMOVE THE LIGHTING SW
·IS THERE CONTINUITY BETWEEN 1 B-12 AND 7 B-12 WHEN
SETTING THE LIGHTING SW AT THE HEADLIGHT POSITION ?REPAIR A POOR CONNECTION AT THE CONNECTORS
OR AN OPEN CIRCUIT BETWEEN THE FUSUBLE LINK
FL-1 (80A) AND 1 B-12
NO
YES
REPAIR OR REPLACE THE LIGHTING SW
NO
REPAIR A POOR CONNECTION AT THE CONNECTORS OR AN
OPEN CIRCUIT BETWEEN THE HARNESS SIDE CONNECTOR
7 B-12 AND B-19
·IS THE DIODE NORMAL?
REPLACE THE DIODE
NOYES

8DÐ138 WIRING SYSTEM
1-2. Headlight On The Left (Or Right) Side Inoperative
1-3. Both Headlights In Low-Beam Inoperative
YES
·IS THE HEADLIGHT BULB ON THE LEFT (OR RIGHT)
SIDE NORMAL?
YES
REPLACE THE FUSE
NO
·IS THE FUSE F-4 (15A) (OR F-5 (15A)) NORMAL?
REPAIR A POOR CONNECTION AT THE CONNECTORS OR AN
OPEN CIRCUIT BETWEEN
FUSE F-4 (15A) AND 3 C-21 (LH)
FUSE F-5 (15A) AND 3 C-32 (RH)REPLACE THE BULB
NO
·
YES
REPAIR A POOR CONNECTION AT THE CONNECTORS OR
AN OPEN CIRCUIT BETWEEN
13 B-12 AND 10 H-15REPAIR OR REPLACE THE DIMMER•PASSING SWNO
·WITH THE SWITCH AT THE LOW-BEAM POSITION, IS
THERE CONTINUITY BETWEEN THE SW CONNECTOR
TERMINALS 13 B-12 AND 16 B-12
DISCONNECT THE DIMMER•PASSING SW CONNECTOR
(COMBINATION SW)

8DÐ140 WIRING SYSTEM
1Ð5. 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-16REPAIR 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 ?
1Ð6. 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 SWREPAIR 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?
NOYES

WIRING SYSTEM 8DÐ141
1-7. Headlight Beam Does Not Change
1-8. Headlights Remain On When The Lighting SW Is Turned Off
YES
·DISCONNECT THE DIMMER•PASSING
SWREPAIR 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

8DÐ142 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