Isuzu N-Series. Manual - part 1131

8-236 CAB AND CHASSIS ELECTRICAL

Driver Side Door Does Not Get Locked (or Unlocked)

FRT Passenger Side Door Does Not Get Locked (or Unlocked)
RR Door-RH Side Does Not Get Locked (or Unlocked)
RR Door-LH Side Does Not Get Locked (or Unlocked)

REPLACE THE DOOR LOCK SWITCH

N8A0216E

REPLACE THE DOOR LOCK ACTUATOR

N8A0217E

CAB AND CHASSIS ELECTRICAL 8-237

Inspection of the Door Lock Circuit
Check the voltage and the continuity between the controller harness side connector terminals.

Termi-

Item

Connect-

Wire

nal

Connected to

to be

ing

Checking conditions

Standard

color

No.

checked

terminal

Unlock

Continuity

1

R/G

1-Ground

Lock

No continuity

Unlock

No continuity

2

G/B

2-Ground

Lock

Continuity

3

B

Ground

3-Ground

-

Continuity

Continuity

4

BR/Y

Actuator

4-5

-

(There is some

(Unlock)

resistance)
Continuity

5

BR/R

Actuator

5-4

-

(There is some

(Lock)

resistance)

6

R

Fuse F-7 (15A)

Voltage

6-Ground

-

Battery voltage

Conti-

nuity

(Resis-

tance)

Door lock SW
(Unlock)

Door lock SW
(Lock)

Driver seat side
door

Driver seat side
door

Harness side

1

2

3

4

5

6

B-12

N8A0218E

8-238 CAB AND CHASSIS ELECTRICAL

Door Lock Controller
The door lock controller sends out to each door lock ac-
tuator the lock/unlock signals received from door lock
switch of driver seat side.

Inspection
Remove the connector of the door lock controller, and
check the continuity and the voltage between the con-
troller side connector terminals.
(Connect the (+) terminal of the battery to 6 

 and

the (

−) terminal to 3 

.)

3 

 — 5 

.................Continuity

3 

 — 4 

.................Continuity

(Then, ground 2 

.)

5 

..................Voltage for approx. 1 second

(Disconnect the ground of 2 

, and ground 1 

.)

4 

..................Voltage for approx. 1 second

Replace the controller when the result of inspection is
found abnormal.

Door Lock Operation Test
After confirming that there is continuity between the har-
ness side connector terminals 4 

 and 5 

 of the

door lock controller, apply battery voltage to each of the
terminals to conduct the operation test.
When the door lock will not operate, check the door lock
actuator for any trouble.

For 24 Volt

For 12V

N8A0219E

B-12

B-12

B-12

B-12

B-12

B-12

B-12

B-12

B-12

B-12

B-12

B-12

Controller side

3

2

1

6

5

4

N8A0220E

B-12

B-12

Connecting terminal

4 (BR/Y)

5 (BR/R)

Operation

Unlock

Lock

Harness
side

1

2

3

4

5

6

B-12

N8A0221E

CAB AND CHASSIS ELECTRICAL 8-239

Door Lock Switch (Driver Seat Side)

The door lock switch on the driver’s door is connected
with the door lock cylinder and the inside lock knob with
a rod. The switch sends lock/unlock signals to the door
lock controller.

Inspection
Check to see if there is any continuity between the con-
nector terminals of the door lock switch.
Replace the switch when the result of inspection is
found abnormal.

Removal and Installation
Refer to Section 2 “CAB AND FRAME” for “DOOR
LOCK ASSEMBLY”.

Door Lock Actuator

Receiving forward or reverse current from the door lock
controller, the door lock actuator locks or unlocks the
door with the rod connected to the door lock mecha-
nism.

Inspection of the Door Lock Actuator
Apply the battery voltage to the connector terminals of
the door lock actuator to check the operation.
When the door lock actuator is checked on the vehicle
and there is no continuity, and when the door lock actu-
ator itself is checked and no trouble is found, check the
circuit between the door lock actuator and the door lock
controller for any failure.

N8A0223E

1

2

3

Lock

Unlock

Terminal

No.

Operation

Switch side

1

2

3

D-4

N8A0224E

N8A0225E