COMBUSTION TYPE POWER HEATER SYSTEM > Power Heater Switch Circuit

for Preparation Click here


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


E176781E01


INSPECTION PROCEDURE

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

1.INSPECT POWER HEATER SWITCH


    E176907E01

  1. Measure the resistance.

    1. Remove the power heater switch.

    2. Disconnect the D9 power heater switch connector.

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

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

  1. Check that the power heater switch 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.

  1. Check that the power heater switch 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.

  1. Install the power heater switch.

  1. Reconnect the power heater switch connector.

Text in Illustration 
*1
Component without harness connected
(Power Heater Switch)


NG
REPLACE POWER HEATER SWITCH (Click here)
OK


2.CHECK HARNESS AND CONNECTOR (POWER HEATER SWITCH - BODY GROUND)


    E176908E01

  1. Disconnect the D9 power heater switch connector.

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    D9-5 (E) - Body ground
    		Always
    		Below 1 Ω

  1. Reconnect the power heater switch connector.

Text in Illustration 
*1
Front view of wire harness connector
(to Power Heater Switch)


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


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


    E176184E03

  1. Disconnect the A45 power heater ECU (combustion heater assembly) connector.

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

    Standard Voltage:
    Tester Connection
    		Switch Condition
    		Specified Condition
    A45-3 (IG) - Body ground
    		Ignition switch ON
    Power heater switch on
    		11 to 14 V
    A45-3 (IG) - Body ground
    		Ignition switch ON
    Power heater switch off
    		Below 1 V

  1. Reconnect the power heater ECU (combustion heater assembly) connector.

Text in Illustration 
*1
Front view of wire harness connector
(to Power Heater ECU (Combustion Heater Assembly))


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

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