Combustion Type Power Heater System Power Heater Alternator Circuit


DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

CHECK HARNESS AND CONNECTOR (HEATER ASSEMBLY - AIR CONDITIONING AMPLIFIER ASSEMBLY)

CHECK HEATER ASSEMBLY

CHECK AIR CONDITIONING AMPLIFIER ASSEMBLY

COMBUSTION TYPE POWER HEATER SYSTEM - Power Heater Alternator Circuit


DESCRIPTION

The heater assembly receives engine operation signals from the air conditioning amplifier assembly. If this circuit is open, the heater assembly will determine that the engine operation signals indicate on. If this circuit is shorted, the heater assembly will determine that the engine operation signals indicate off and the heater assembly will not operate.

WIRING DIAGRAM


Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.Heating Air Conditioning.Air Conditioning System (For Automatic Air Conditioning System).Combustion Type Power Heater System Power Heater Alternator Circuit


INSPECTION PROCEDURE

1.CHECK HARNESS AND CONNECTOR (HEATER ASSEMBLY - AIR CONDITIONING AMPLIFIER ASSEMBLY)

  1. Disconnect the A97 heater assembly connector.

  1. Disconnect the G25 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
    A97-8 (+) - G25-18 (HTR1)
    		Always
    		Below 1 Ω
    A97-8 (+) - Body ground
    		Always
    		10 kΩ or higher


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


2.CHECK HEATER ASSEMBLY

  1. Disconnect the G25 air conditioning amplifier assembly connector.



    Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.Heating Air Conditioning.Air Conditioning System (For Automatic Air Conditioning System).Combustion Type Power Heater System Power Heater Alternator Circuit

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

    Standard Voltage:
    Tester Connection
    		Condition
    		Specified Condition
    G25-18 (HTR1) - Body ground
    		Engine idling, heater switch assembly (power heater switch) off
    		Below 1 V
    Engine idling, heater switch assembly (power heater switch) on
    		11 to 14 V
    Text in Illustration
    *a
    		Rear view of wire harness connector
    (to Air Conditioning Amplifier Assembly)


NG
REPLACE HEATER ASSEMBLY (LandCruiser RM000005TN8000X.html)
OK


3.CHECK AIR CONDITIONING AMPLIFIER ASSEMBLY


    Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.Heating Air Conditioning.Air Conditioning System (For Automatic Air Conditioning System).Combustion Type Power Heater System Power Heater Alternator Circuit

  1. Remove the air conditioning amplifier assembly with its connectors still connected (LandCruiser RM0000039R5028X.html)

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

    Standard Voltage:
    Tester Connection
    		Condition
    		Specified Condition
    G25-18 (HTR1) - G25-14 (GND)
    		Engine idling
    		11 to 14 V
    Text in Illustration
    *a
    		Component with harness connected
    (Air Conditioning Amplifier Assembly)


NG
REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY (LandCruiser RM0000039R5028X.html)
OK

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE (LandCruiser RM0000027G700WX.html)