COMBUSTION TYPE POWER HEATER SYSTEM > Power Heater Switch Circuit

for Preparation Click here


DESCRIPTION

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

WIRING DIAGRAM


E184679E03


INSPECTION PROCEDURE

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

HINT:
Before performing the following procedures, check the battery and generator assembly and confirm that they are operating normally.
1.INSPECT HEATER SWITCH ASSEMBLY (POWER HEATER SWITCH)


    E176907E02

  1. Remove the heater switch assembly (Click here).

  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 on
    		Below 1 Ω
    4 (IG) - 1 (IN)
    		Heater switch off
    		10 kΩ or higher

  1. Apply battery voltage to the power heater switch and check that the operation indicator comes on.

    OK:
    Measurement Condition
    		Specified Condition
    Battery positive (+) → Terminal 1 (IN)
    Battery negative (-) → Terminal 5 (E)
    		Indicator comes on

  1. Apply battery voltage to the power heater switch and check that the illumination comes on.

    OK:
    Measurement Condition
    		Specified Condition
    Battery positive (+) → Terminal 3 (ILL+)
    Battery negative (-) → Terminal 2 (ILL-)
    		Illumination comes on


NG
REPLACE HEATER SWITCH ASSEMBLY (Click here)
OK


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


    E176908E04

  1. Disconnect the E1 switch connector.

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    E1-5 (E) - Body ground
    		Always
    		Below 1 Ω
    Text in Illustration 
    *1
    		Front view of wire harness connector
    (Heater Switch Assembly [Power Heater Switch])


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


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


    E176184E14

  1. Disconnect the A31 heater connector.

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

    Standard Voltage:
    Tester Connection
    		Switch Condition
    		Specified Condition
    A31-3 (IG) - Body ground
    		Ignition switch ON
    Heater switch on
    		11 to 14 V
    A31-3 (IG) - Body ground
    		Ignition switch ON
    Heater switch off
    		Below 1 V
    Text in Illustration 
    *1
    		Front view of wire harness connector
    (to Heater Assembly)


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

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