Isuzu D-Max / Isuzu Rodeo (TFR/TFS). Manual - part 1193

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