Isuzu KB P190. Manual — part 1274

8A-158 ELECTRICAL-BODY AND CHASSIS

CIRCUIT DIAGRAM 4JA1T (L), 4JH1-TC, 4JJ1-TC, 4JK1-TC (HALOGEN PROJECTOR
TYPE)

RTW78AXF004301

ELECTRICAL-BODY AND CHASSIS 8A-159

CIRCUIT DIAGRAM 4JA1T (L), 4JH1-TC, 4JJ1-TC, 4JK1-TC (CLEARANCE LIGHT,
LICENSE PLATE LIGHT, TAIL LIGHT)

RTW78AXF026701

8A-160 ELECTRICAL-BODY AND CHASSIS

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

B60

-

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

X6

- ground and

2

X6

- 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 (C2),
(C36)

Repair open circuit

Wiring continuity between

B60

-

C2

Open circuit

NG

OK

ELECTRICAL-BODY AND CHASSIS 8A-161

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
4

X4

- ground and

4

B60

- 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

C19

- fuse No.

EB7 or 3

C26

fuse No.

EB8

Open circuit and/or poor
connector contact

NG

OK

Reinstall or replace fuse No.
EB7 or No. EB8

Fuse No. EB7 (10A) or
No. EB8 (10A) (Relay and
fuse box)
(No. EB7 RH, No. EB8: 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