Isuzu N-Series. Manual - part 1157

8-340 CAB AND CHASSIS ELECTRICAL

Installation
To install, follow the removal steps in the reverse order.

SRS Control System

General Description

SRS airbag supplements the driver’s seat belt protec-
tion by deploying airbag at the top center of the steering
column.
SRS airbag deploys in case of front collision over certain
degree of impact.
This system consists of SRS control unit, driver’s SRS
airbag, SRS coil assembly, exclusive wire harness, and
“SRS” warning lamp in the meter and forms a deploy-
ment circuit.
A sensor is equipped to this circuit to convert the impact
into an electrical signal in case of front collision over cer-
tain degree of impact. The electrical signal generated at
this time will be processed in the SRS control unit to
compare with the value stored in the memory.
When the generated signal exceeds the setting value,
SRS control unit sends sufficient current to SRS airbag
for deployment.

Parts Location

N8A0364E

A-1 AIR BAG

BATTERY

FL-2 FUSIBLE LINK

B-1 EARTH; FRAME LH (FRONT)

FUSE BOX ASM
F-16, F-18

B-79 DATA LINK CONNECTOR 

B-51 SRS WARNING LIGHT

(METER)

B-244 SRS COIL

B-67

B-276 SRS COUPLING 

CONNECTOR

B-243 SRS CONTROL UNIT

H-7

B-275 EARTH; FRAME RH (FRONT)

N9A0066E

CAB AND CHASSIS ELECTRICAL 8-341

Circuit Diagram

0.85

B

1.25 B

0.5
SB

0.5

B

0.5

B

0.5

B/R

0.5

B/Y

0.5

W/R

0.5

W/R

0.85

B

0.5

B/R

0.5

B/R

0.5

B/R

0.5
GY

0.5

B

0.5

B

0.5
SB

0.5
GY

FRAME

P-5

P-1

P-2

P-3

P-4

FL-2

KEY SW

STARTER SWITCH

METER

AIR BAG

SRS COUPLING 
CONNECTOR

SHORTING 
CONNECTOR

SHORTING 
CONNECTOR

SRS COIL

AIR BAG

SRS CONTROL UNIT

SRS COUPLING 
CONNECTOR

DATA LINK CONNECTOR

B-1

B-1

B-275

FRAME LH (FRONT)

FRAME LH (FRONT)

FRAME RH (FRONT)

3.0
W/L

3.0 W/L

3.0 B/Y

8.0B

2L

40A

H-7

1

B-67

B-67

2

3

OFF

ACC

ON

ST

F-16 10A

METER

F-18 10A

SRS

B-51

18

B-276

4

B-276

1

B-276

B-243

B-243

2

15

B-243

B-276

B-276

B-276

19

B-79

5

B-79

4

4

B-243

16

6

7

B-79

B-79

7

13

8

B-243

6

B-243

5

14

B-51

1

B-244

2

B-244

B-243

18

B-243

20

B-243

8

B-243

A-1

A-1

7

0.5

Y

0.5

Y/B

N9A0085E

8-342 CAB AND CHASSIS ELECTRICAL

Connector List

No.

Connector Face

A-1

A-1

B-1

B-51

B-67

B-67

B-79

B-243

002-045

002-046

000-001

020-004

004-002

2
4

1
3

004-001

1

2

3

4

016-005

8

7

6

5

4

3

2

1

16

15

14

13

12

11

10

9

021-001

No.

Connector Face

B-244

B-244

B-275

B-276

B-276

P-1

P-2

P-3

002-043

002-044

000-020

008-009

1 2

3

8

4 5 6 7

008-010

1

2

3

8

4

5

6

7

000-004

000-006

000-006

CAB AND CHASSIS ELECTRICAL 8-343

H-7

Heater and Air Conditioning

General Description
The air conditioning consists of compressor, evaporator,
condenser, A/C switch, fan switch, etc. When the engine
is rotating, the A/C starts to work with both the A/C and
fan switches “ON”, followed by the engagement of the
magnetic clutch. It stops to work when either the fan
switch or the A/C switch turns “OFF”. In addition to the
switches, the A/C has the function of temporary stop of
its operation by the sensing system in the A/C cycle,
such as:

• sensing abnormal rise of the refrigerant pressure

by means of the pressure switch.

• sensing temperature of the blowing-off air by

means of the thermo switch preventing the evapo-
rator from freezing.

• sensing the coolant temperature by the thermo

switch (available for limited models only).

When fan control knob (fan switch) is put on with temp.
Control lever being in the “FULL HOT” position (FULL
HOT switch on) ceramic heater within heater unit gener-

ates heat, raising a heater blow-off temperature to en-
hance heating performance.

No.

Connector Face

P-4

P-5

000-004

000-002

1

2

1

2

1 2 3 4

5 6 7 8

9 10 11 12 13

14 15 16 17 18

2

1

2

1

4 3 2 1

8 7 6 5

13 12 11 10 9

18 17 16 15 14

H - 6

H - 7

H - 8

N8A5489E