Isuzu D-Max / Isuzu Rodeo (TFR/TFS). Manual - part 1503

8-112  ELECTRICAL-BODY AND CHASSIS

ELECTRICAL-BODY AND CHASSIS  8-113

TROUBLE SHOOTING

HEADLIGHT

1. Both the headlights (high and low beam) do not light

Checkpoint

Trouble Cause

Countermeasure

Repair the wiring

Poor ground point contact

NG

Repair open circuit or

connector contact

Repair open circuit

Repair or replace the

combination switch

Voltage between 1 

C-42

 -

ground

Open circuit between lighting

relay and lighting switch

Open circuit between battery

positive terminal and lighting

relay

Combination switch continuity

Poor switch contact or sw

faulty

Voltage between

5 

X-1

 - ground and

2 

X-1

 - ground

Reinstall or replace the

lighting relay

Lighting relay

Poor relay contact or relay

faulty

NG

NG

NG

NG

OK

OK

OK

OK

Ground point contact (C-2)

Repair open circuit

Wiring continuity between

7 

C-42

 - 

C-2

 and

16 

C-42

 - 

C-2

Open circuit

NG

OK

8-114  ELECTRICAL-BODY AND CHASSIS

2. High or low beam does not light on both headlights

Checkpoint

Trouble Cause

Countermeasure

Repair or replace the

combination switch

Dimmer

⋅passing switch

continuity

Poor switch contact or switch

faulty

NG

Repair open circuit or

connector contact

Voltage between

13 

C-42

 - ground and

15 

C-42

 - ground

Open circuit between

headlight and dimmer

⋅passing

switch

NG

OK

3. RH (or LH) high and low beam does not light

Replace the headlight bulb

Headlight connector continuity

Blown filament or air leakage

NG

Repair or replace the wire

and/or connector

Wiring continuity between
connector 3 

C-19

 - fuse No.

EB-9 or 3 

C-26

 fuse No.

EB-8

Open circuit and/or poor

connector contact

NG

OK

Reinstall or replace fuse No.

EB-8 or No. EB-9

Fuse No. EB-8 (10A) or
No. EB-9 (10A) (Relay and
fuse box)
(No. EB-9 RH, No. EB-8: LH)

Poor installation or blown fuse

NG

OK

4. High or low beam does not light on one headlight (RH or LH)

Replace the headlight

assembly

Headlight connector continuity

Blown filament

NG

Repair open circuit or

connector contact

Wiring continuity between

headlight and dimmer

⋅passing

switch

Open circuit between

headlight and dimmer

⋅passing

switch

NG

OK

ELECTRICAL-BODY AND CHASSIS  8-115

5. Headlight does not go out

Checkpoint

Trouble Cause

Countermeasure

Replace the lighting relay

Lighting relay continuity
between connector 1 

X-1

- 5 

X-1

  (Should be no

continuity)

Relay point fused

NG

Replay the combination switch

Lighting switch continuity
between connector 1 

C-42

-7 

C-42

 when switch is

OFF(Should be no continuity)

point fused or faulty

NG

OK

OK

Repair or replace the

combination switch

Dimmer

⋅passing switch con-

tinuity between connector
14 

C-42

 - 16 

C-42

 when

switch is not operating
(Should be no continuity)

Switch point fused or faulty

NG

Repair short circuit

between 4 

X-1

 - 1 

C-42

and 4 

X-1

 - 14 

C-42

Check if headlight goes out

when connector 

C-42

 is

disconnected

Short circuit

NG

OK

6. Insufficient headlight brightness

Replace the headlight bulb

Headlight bulb

Bulb filament faulty

NG

Repair the wiring

Dimmer

⋅passing switch

Wire continuity between con-

nector 16 

C-42

 - 

C-2

Poor ground point contact

NG

OK

Clean the light lens

Headlight lens

Lens dirty

NG

OK