Isuzu Trooper (2000 year). Manual - part 10

 

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Isuzu Trooper (2000 year). Manual - part 10

 

 

HEATING, VENTILATION AND AIR CONDITIONING (HVAC)

1A–9

Diagnosis

Heating Cycle diagnosis

Condition

Possible cause

Correction

No heating or insufficient heating.

Blower motor does not run or runs
improperly.

Refer to “FAN CONTROL LEVER
(FAN SWITCH) DIAGNOSIS”.

Engine coolant temperature is low.

Check the engine coolant
temperature after warming up the
engine and check the thermostat.
Replace as necessary.

Insufficient engine coolant.

Add engine coolant as required.

Circulation volume of engine coolant
is insufficient.

Check if the water hose to the heater
core is clogged, collapsed or twisted.
Repair or replace as necessary.

Heater core clogged or collapsed.

Clean or replace as necessary.

The heater cores is not provided with
air sent from the blower motor.

Repair the temperature control link
unit or mode doors.

Duct connections defective or
unsealing.

Repair or replace as necessary.

Control lever moves but mode door
does not operate

Cable attaching clip is not correct.

Repair

does not operate.

Link unit of heater or blower
assembly defective.

Repair

The mode door cannot be set to the
mode selected.

Link unit of heater unit or blower
assembly defective.

Repair.

Control cable is not adjusted.

Adjust.

1A–10 HEATING, VENTILATION AND AIR CONDITIONING (HVAC)

Fan Control Lever (Fan Switch) Diagnosis

Current flows to the blower motor through the heater and
the A/C relay (B-36) to activate the rotation of the blower
motor by turning “ON” the fan control knob (fan switch).
Blower motor speed is controlled in stages by the resistor,
by operating the switch from “LOW” to “HIGH”.

For the inspection of the relays, switches and units in
each table, refer to “INDIVIDUAL INSPECTION” in this
section.

D01RS004

Condition

Possible cause

Correction

Blower motor does not run.

—

Refer to Chart A

Blower motor does not run in certain
position (s).

—

Refer to Chart B, C, D and E

Blower motor does not stop at “OFF”
position.

—

Refer to Chart F

HEATING, VENTILATION AND AIR CONDITIONING (HVAC)

1A–11

Chart “A” Blower Motor Dose Not Run 

Step

Action

Yes

No

1

Is relay (B-36) OK?

Go to Step 2

Replace

2

Is fuse C-19 (25A) OK?

Go to Step 3

Replace

3

Is resistor OK?

Go to Step 4

Replace

4

Is fan control knob OK?

Go to Step 5

Replace control

lever assembly.

5

Is blower motor OK?

Go to Step 6

Replace

6

1. Turn the ignition switch “ON”.
2. Turn fan control knob “ON”.
3. Check to see if battery voltage is present at chassis side

connector terminal No. B5-1

Is there a battery voltage?

Poor ground or

open circuit either

between chassis

side connector

terminal No. B5-2

and No. B3-2 or

No. I18-1 and

body ground (No.

B-2).

Open circuit

between No.

C-19 (25A) fuse

and No. B5-1.

Chart “B” Blower Motor Does Not Run At Low Position 

Step

Action

Yes

No

1

Is resistor OK?

Go to Step 2

Replace

2

Is fan control knob (Fan Switch) OK?

Open circuit

between chassis

side connector

terminal No. B3-1

and No.I18-2.

Replace control

lever assembly.

Chart “C” Blower Motor Dose Not Run At Medium Low Position 

Step

Action

Yes

No

1

Is resistor OK?

Go to Step 2

Replace

2

Is fan control knob (Fan Switch) OK?

Open circuit

between the
chassis side

connector

terminal No. B3-4

and No. I18-5.

Replace control

lever assembly.

Chart “D” Blower Motor Dose Not Run At Medium High Position 

Step

Action

Yes

No

1

Is resistor OK?

Go to Step 2

Replace

2

Is fan control knob (Fan Switch) OK?

Open circuit

between chassis

side connector

terminal No. B3-6

and No. I18-3.

Replace control

lever assembly.

1A–12 HEATING, VENTILATION AND AIR CONDITIONING (HVAC)

Chart “E” Blower Motor Dose Not Run At High Position 

Step

Action

Yes

No

1

Is resistor OK?

Go to Step 2

Replace

2

Is fan control knob (Fan Switch) OK?

Open circuit

between Chassis

side connector

terminal No. B3-3

and No. I18-6.

Replace control

lever assembly.

Chart “F” Blower Motor Does Not Stop In The “OFF” Position 

Step

Action

Yes

No

1

Is the fan control knob (Fan Switch) OK?

Short circuit

between chassis

side connector

terminal No. B5-2

and

No. B3-2,No. B3-

3 and No. I18-6,

No. B3-6 and

No. I18-3,

No. B3-4 and

No. I18-5 or

No. B3-1 and

No. I18-2

Replace control

lever assembly.

Individual Inspection

Blower Motor

1. Disconnect the blower motor (B-5) connector from

the blower motor.

2.  Connect the battery positive terminal to the No. 1

terminal of the blower motor and the negative to the
No. 2.

3. Be sure to check to see if the blower motor operates

correctly.

873RS005

Resistor

1. Disconnect the resistor (B-3) connector.
2. Check for continuity and resistance between the

terminals of the resistor.

840RS001

 

 

 

 

 

 

 

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