Combustion Type Power Heater System Power Heater Switch Circuit


DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

CHECK HARNESS AND CONNECTOR (HEATER SWITCH ASSEMBLY - BATTERY AND BODY GROUND)

INSPECT HEATER SWITCH ASSEMBLY (POWER HEATER SWITCH)

CHECK HARNESS AND CONNECTOR (HEATER SWITCH ASSEMBLY - HEATER ASSEMBLY)

COMBUSTION TYPE POWER HEATER SYSTEM - Power Heater Switch Circuit


DESCRIPTION

When the heater switch assembly (power heater switch) is turned on, the heater assembly sends a drive signal to the heater pump assembly. The heater assembly then receives the fuel necessary for combustion and starts operating.

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 Switch Circuit


INSPECTION PROCEDURE

NOTICE:
Inspect the fuses for circuits related to this system before performing the following inspection procedure.
1.CHECK HARNESS AND CONNECTOR (HEATER SWITCH ASSEMBLY - BATTERY AND BODY GROUND)


    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 Switch Circuit

  1. Disconnect the heater switch assembly (power heater switch) connector.

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

    Standard Voltage:
    Tester Connection
    		Switch Condition
    		Specified Condition
    G177-4 (IG) - Body ground
    		Engine switch on (IG)
    		11 to 14 V
    G177-4 (IG) - Body ground
    		Engine switch off
    		Below 1 V

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    G177-5 (E) - Body ground
    		Always
    		Below 1 Ω
Text in Illustration
*a
Front view of wire harness connector
(to Heater Switch Assembly [Power Heater Switch])


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


2.INSPECT HEATER SWITCH ASSEMBLY (POWER HEATER SWITCH)
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 Switch Circuit

  1. Remove the heater switch assembly (power heater switch) (LandCruiser RM000003SAI02TX.html).

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

    Standard Resistance:
    Tester Connection
    		Switch Condition
    		Specified Condition
    4 (IG) - 1 (IN)
    		Heater switch assembly (power heater switch) on
    		Below 1 Ω
    4 (IG) - 1 (IN)
    		Heater switch assembly (power heater switch) off
    		10 kΩor higher

  1. Check operation indicator.

    1. Turn the heater switch assembly (power heater switch) on.

    2. Connect a positive (+) lead from the battery to terminal 4 (IG) and a negative (-) lead to terminal 5 (E), and check that the operation indicator comes on.

      Result
      Result
      		Proceed to
      Indicator comes on
      		A
      Indicator does not come on
      		B


B
REPLACE HEATER SWITCH ASSEMBLY (POWER HEATER SWITCH) (LandCruiser RM000003SAI02TX.html)
A


3.CHECK HARNESS AND CONNECTOR (HEATER SWITCH ASSEMBLY - HEATER ASSEMBLY)

  1. Disconnect the G177 heater switch assembly (power heater switch) connector.

  1. Disconnect the A97 heater assembly connector.

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

    Standard Resistance:
    Tester Connection
    		Switch Condition
    		Specified Condition
    G177-1 (IN) - A97-3 (IG)
    		Always
    		Below 1 Ω
    A97-3 (IG) - Body ground
    		Always
    		10 kΩor higher


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

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