COMBUSTION TYPE POWER HEATER SYSTEM Power Heater Switch Circuit

DESCRIPTION

When the power heater switch 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

A005M01E03

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. A005K0CE03
      Text in Illustration
      *a

      Component without harness connected

      (Power Heater Switch)

      Measure the resistance.


      1. Remove the heater switch assembly.

      2. Disconnect the F44 power heater switch connector.

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

        Standard Resistance (Check for Open)
        Tester Connection Condition Specified Condition
        F44-4 (IG) - F44-1 (IN) Power heater switch on Below 1 Ω
        Standard Resistance (Check for Short)
        Tester Connection Condition Specified Condition
        F44-4 (IG) - F44-1 (IN) Power 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 (POWER HEATER SWITCH - BODY GROUND)


    1. 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) - BATTERY)


    1. A005MELE02

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

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      A29-3 (IG) - Body ground

      Ignition switch ON

      Power heater switch on

      		 11 to 14 V
      A29-3 (IG) - Body ground

      Ignition switch ON

      Power heater switch off

      		 Below 1 V
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Power Heater ECU (Combustion Heater Assembly))

    OK

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

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR