Air Conditioning System (For Automatic Air Conditioning System) Vehicle Speed Signal Circuit

Vehicle Interior. Hilux. Tgn26, 36 Kun25, 26, 35, 36 Ggn25
Heating Air Conditioning. Hilux. Tgn26, 36 Kun25, 26, 35, 36 Ggn25

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

CHECK AIR CONDITIONING AMPLIFIER ASSEMBLY

CHECK HARNESS AND CONNECTOR (COMBINATION METER - AIR CONDITIONING AMPLIFIER)

CHECK COMBINATION METER ASSEMBLY

AIR CONDITIONING SYSTEM (for Automatic Air Conditioning System) - Vehicle Speed Signal Circuit


DESCRIPTION

The air conditioning amplifier assembly monitors signals from the speedometer sensor via the combination meter. The air conditioning amplifier assembly uses these signals to adjust the thermistor signal.

WIRING DIAGRAM


Hilux. Tgn26, 36 Kun25, 26, 35, 36 Ggn25.Heating Air Conditioning.Air Conditioning System (For Automatic Air Conditioning System).Air Conditioning System (For Automatic Air Conditioning System) Vehicle Speed Signal Circuit


INSPECTION PROCEDURE

HINT:
Check that the speedometer in the combination meter assembly operates normally before inspecting the vehicle speed signal circuit (HILUX_TGN26 RM000002UD7086X.html).
1.CHECK AIR CONDITIONING AMPLIFIER ASSEMBLY


    Hilux. Tgn26, 36 Kun25, 26, 35, 36 Ggn25.Heating Air Conditioning.Air Conditioning System (For Automatic Air Conditioning System).Air Conditioning System (For Automatic Air Conditioning System) Vehicle Speed Signal Circuit

  1. Remove the air conditioning amplifier assembly with its connectors still connected (HILUX_TGN26 RM000001K3A01QX.html).

  1. Using an oscilloscope, check the waveform of the air conditioning amplifier assembly.

    Measurement Condition
    Item
    		Content
    Tester Connection
    		G94-9 (SPD) - Body ground
    Tool Setting
    		5 V/DIV., 20 ms./DIV.
    Condition
    		Driving at approximately 20 km/h (12 mph)
    OK:
    Waveform is as shown in the illustration.
    Text in Illustration
    *a
    		Component with harness connected
    (Air Conditioning Amplifier Assembly)
    HINT:
    As the vehicle speed increases, the wavelength becomes shorter.


NG
Go to step 2
OK

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE (HILUX_TGN26 RM0000045E301DX.html)

2.CHECK HARNESS AND CONNECTOR (COMBINATION METER - AIR CONDITIONING AMPLIFIER)

  1. Disconnect the G19 combination meter assembly connector.

  1. Disconnect the G94 air conditioning amplifier assembly connector.

  1. Measure the resistance according to the value(s) in the table below.

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    G19-6 (+S) - G94-9 (SPD)
    		Always
    		Below 1 Ω
    G94-9 (SPD) - Body ground
    		Always
    		10 kΩ or higher


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


3.CHECK COMBINATION METER ASSEMBLY


    Hilux. Tgn26, 36 Kun25, 26, 35, 36 Ggn25.Heating Air Conditioning.Air Conditioning System (For Automatic Air Conditioning System).Air Conditioning System (For Automatic Air Conditioning System) Vehicle Speed Signal Circuit

  1. Remove the combination meter with its connector still connected (HILUX_TGN26 RM000000THS029X.html).

  1. Using an oscilloscope, check the waveform of the combination meter assembly.

    Measurement Condition
    Item
    		Content
    Tester Connection
    		G19-6 (+S) - Body ground
    Tool setting
    		5 V/DIV., 20 ms./DIV.
    Condition
    		Driving at approximately 20 km/h (12 mph)
    OK:
    Waveform is as shown in the illustration.
    Text in Illustration
    *a
    		Component with harness connected
    (Combination Meter Assembly)
    HINT:
    As the vehicle speed increases, the wavelength becomes shorter.


NG
REPLACE COMBINATION METER ASSEMBLY (HILUX_TGN26 RM000000THS029X.html)
OK

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY (HILUX_TGN26 RM000001K3A01QX.html)