Isuzu D-Max / Isuzu Rodeo (TFR/TFS). Manual - part 1539

8-256  ELECTRICAL-BODY AND CHASSIS

Thermo Unit Inspection

The thermo unit is thermistor type and must be inspected
under the conditions as shown in the left chart.
1. Put  the  deviation  of  the  galvanometer  to  0  by  using  the

variable  resistor,  switch  the  thermo  unit  off  and  then

measure the resistance of the resistor through the bridge.

Confirm  that  the  resistance  is  continuously  variable  in  any

other points than those shown in the following table.

2. Dip the thermo unit into 80 - 90

°C (176 - 194°F) water and

confirm  that  there  is  no  bubble  continuously  coming  out  of

inside of the unit.

Replace  the  unit  when  the  result  of  inspection  is  found

abnormal.

Temperature

Check

condition

50

°C

(122

°F)

115

°C

(239

°F)

7V 55 

Ω

Gauge

Resistance

+33.6

226.0 

-36.6

+1.71

26.4 

-2.21

7V 25 

Ω

Gauge

value (

Ω)

-

+2.68

24.3 

-3.68

ELECTRICAL-BODY AND CHASSIS  8-257

FUEL GAUGE AND TANK UNIT

Fuel gauge On-Vehicle Inspection

1. Disconnect the fuel gauge wire connector.

2. Connect a 3.4 Watt test bulb 

1

 to the ground.

The  gauge  needle  should  more  the  middle  part  of  the

gauge.

Fuel Gauge Off-Vehicle Inspection

Use a circuit tester to measure the fuel gauge resistance.
Fuel Gauge Resistance

Ω

Standard

Measuring Point

With

Tachometer

Without

Tachometer

IGN (+) - Ground

223

110

IGN (+) - 7V

(0)

IGN (+) - UNIT

83

25

Ground - 7V

110

Ground - UNIT

140

135

7V - UNIT

25

8-258  ELECTRICAL-BODY AND CHASSIS

Fuel Tank Unit Inspection

Measure the fuel tank unit resistance between the connector
terminals 1 

F-1

 and 3 

F-1

 while shifting the float from “E”

to “F” point.

Fuel Tank Resistance

Level

Float position

mm

Standard resistance

Ω

F (B)

51.7

17 

± 2.1

1/2 (A)

49.4

45 

± 4.5

E (C)

166.9

120 

± 6.5

ELECTRICAL-BODY AND CHASSIS  8-259

Low Fuel Indicator Light Inspection

1. Disconnect the fuel tank unit wire connector.

2. Connect between terminal (YL) and (B).

3. Turn the key switch on. Check that the bulb lights.
If operation is not correct, remove and check the bulb or circuit.

Check level sensor operation

1. Remove the fuel tank unit.

2. Apply battery voltage between terminal (YL) and (B) through

a 3.4 watt bulb. Check that the bulb lights.

Note:
It will take a short time for the bulb light.
3. Submerge the sensor in fuel. Check that the bulb goes out.
If operation is not correct, replace the fuel tank unit.

BRAKE SYSTEM WARNING LIGHT

The brake system warning light comes on while the parking
brake is set and the starter key is ON position.
Note:
The parking brake indicator light circuit is designed to
prevent driving of the vehicle with the parking brake on.
It does not indicate the condition of the parking brake
system.

The parking brake switch is in parallel with the brake fluid
switch.

The brake system warning light also comes on when reservoir
brake fluid level falls below the specified limit with the parking
brake released and the starter switch is ON position.