COMBUSTION TYPE POWER HEATER SYSTEM Power Heater Switch Circuit

DESCRIPTION

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

WIRING DIAGRAM

A01VLB6E03

CAUTION / NOTICE / HINT

Note

Inspect the fuses for circuits related to this system before performing the following inspection procedure.

PROCEDURE


  1. INSPECT HEATER SWITCH ASSEMBLY


    1. A01VGW5E04
      Text in Illustration
      *a

      Component without harness connected

      (Heater Switch Assembly)

      Measure the resistance.


      1. Remove the heater switch assembly.

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

        Standard Resistance
        Tester Connection Switch Condition Specified Condition
        F44-4 (IG) - F44-1 (IN) Heater switch on Below 1 Ω
        F44-4 (IG) - F44-1 (IN) Heater switch off 10 kΩ or higher

    2. Check that the heater switch assembly operation indicator comes on.


      1. Connect the positive (+) lead from the battery to terminal 1 (IN) and the negative (-) lead to terminal 5 (E), and check that the operation indicator comes on.

        OK
        Indicator comes on.

    3. Check that the heater switch assembly illumination comes on.


      1. Connect the positive (+) lead from the battery to terminal 3 (ILL+) and the negative (-) lead to terminal 2 (ILL-), and check that the switch illumination comes on.

        OK
        Illumination comes on.

    NG

    REPLACE HEATER SWITCH ASSEMBLY Click here

    OK

  2. CHECK HARNESS AND CONNECTOR (HEATER SWITCH ASSEMBLY - IG1 NO. 1 RELAY AND BODY GROUND)


    1. A01VH63E01
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Heater Switch Assembly)

      Disconnect the F44 heater switch assembly connector.

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      F44-4 (IG) - Body ground Ignition switch ON 11 to 14 V

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      F44-5 (E) - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

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


    1. Disconnect the A29 power heater ECU (combustion heater assembly) connector.

    2. Disconnect the F44 heater switch assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A29-3 (IG) - F44-1 (IN) Always Below 1 Ω
      A29-3 (IG) - Body ground Always 10 kΩ or higher

    OK

    PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR