AIR CONDITIONING SYSTEM(for Automatic Air Conditioning System) PTC Heater Circuit

DESCRIPTION

PTC heater relays are closed in accordance with signals from the air conditioning amplifier assembly and power is supplied to the quick heater assembly installed on the radiator heater unit.

WIRING DIAGRAM

B001H0TE09

CAUTION / NOTICE / HINT

Note

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

PROCEDURE


  1. INSPECT PTC HEATER RELAY (PTC NO.1 OR 400W INV, PTC NO.2, PTC NO.3)


    1. B001D64

      Remove the PTC NO.1 or 400W INV, PTC NO.2 and PTC NO.3 relays from the engine room No. 3 relay block.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      3 - 5 Battery voltage is not applied to terminals 1 and 2 10 kΩ or higher
      Battery voltage is applied to terminals 1 and 2 Below 1 Ω

    NG

    REPLACE PTC HEATER RELAY (PTC NO.1 OR 400W INV, PTC NO.2, PTC NO.3)

    OK

  2. CHECK AIR CONDITIONING AMPLIFIER ASSEMBLY


    1. B001DK9E01
      Text in Illustration
      *a

      Component with harness connected

      (Air Conditioning Amplifier Assembly)

      Remove the air conditioning amplifier assembly with its connectors still connected Click here.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      G25-3 (PTC1) - Body ground

      • Engine running (1250 rpm or more)

      • Temperature setting MAX HOT

      • Outside temperature 10°C (50°F) or less

      • Engine coolant temperature 79°C (174°F) or less

      • Headlight dimmer switch off

      • Blower switch off

      		 11 to 14 V
      G25-22 (PTC2) - Body ground

      • Engine running (1250 rpm or more)

      • Temperature setting MAX HOT

      • Outside temperature 10°C (50°F) or less

      • Engine coolant temperature 76°C (169°F) or less

      • Headlight dimmer switch off

      • Blower switch off
      G25-4 (PTC3) - Body ground

      • Engine running (1250 rpm or more)

      • Temperature setting MAX HOT

      • Outside temperature 10°C (50°F) or less

      • Engine coolant temperature 73°C (163°F) or less

      • Headlight dimmer switch off

      • Blower switch off
      G25-3 (PTC1) - Body ground

      • Engine running (1250 rpm or more)

      • Temperature setting MAX HOT

      • Outside temperature 10°C (50°F) or less

      • Engine coolant temperature 79°C (174°F) or less

      • Headlight dimmer switch off

      • Blower switch on

      		 Below 1 V
      G25-22 (PTC2) - Body ground

      • Engine running (1250 rpm or more)

      • Temperature setting MAX HOT

      • Outside temperature 10°C (50°F) or less

      • Engine coolant temperature 76°C (169°F) or less

      • Headlight dimmer switch off

      • Blower switch on
      G25-4 (PTC3) - Body ground

      • Engine running (1250 rpm or more)

      • Temperature setting MAX HOT

      • Outside temperature 10°C (50°F) or less

      • Engine coolant temperature 73°C (163°F) or less

      • Headlight dimmer switch off

      • Blower switch on

    NG

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

    OK

  3. CHECK HARNESS AND CONNECTOR (ENGINE ROOM NO. 3 RELAY BLOCK - AIR CONDITIONING AMPLIFIER)


    1. Remove the PTC heater relays from the engine room No. 3 relay block.

    2. Disconnect the G25 amplifier connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      PTC NO.1 or 400W INV relay terminal 1 - G25-3 (PTC1) Always Below 1 Ω
      PTC NO.2 relay terminal 1 - G25-22 (PTC2)
      PTC NO.3 relay terminal 1 - G25-4 (PTC3)
      PTC NO.1 or 400W INV relay terminal 1 - Body ground Always 10 kΩ or higher
      PTC NO.2 relay terminal 1 - Body ground
      PTC NO.3 relay terminal 1 - Body ground

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. CHECK HARNESS AND CONNECTOR (ENGINE ROOM NO. 3 RELAY BLOCK - QUICK HEATER)


    1. Remove the PTC heater relays from the engine room No. 3 relay block.

    2. Disconnect the G28 quick heater connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      PTC NO.1 or 400W INV relay terminal 3 - G28-2 (B) Always Below 1 Ω
      PTC NO.2 relay terminal 3 - G28-3 (B)
      PTC NO.3 relay terminal 3 - G28-1 (B)
      PTC NO.1 or 400W INV relay terminal 3 - Body ground Always 10 kΩ or higher
      PTC NO.2 relay terminal 3 - Body ground
      PTC NO.3 relay terminal 3 - Body ground

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  5. CHECK HARNESS AND CONNECTOR (ENGINE ROOM NO. 3 RELAY BLOCK - BATTERY AND BODY GROUND)


    1. B001GZ5E02
      Text in Illustration
      *1 PTC NO.1 or 400W INV Relay
      *2 PTC NO.2 Relay
      *3 PTC NO.3 Relay
      *a

      Component without relay installed

      (Engine Room No. 3 Relay Block)

      Remove the PTC heater relays from the engine room No. 3 relay block.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      PTC NO.1 or 400W INV relay terminal 5 - Body ground Always 11 to 14 V
      PTC NO.2 relay terminal 5 - Body ground
      PTC NO.3 relay terminal 5 - Body ground

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      PTC NO.1 or 400W INV relay terminal 2 - Body ground Always Below 1 Ω
      PTC NO.2 relay terminal 2 - Body ground
      PTC NO.3 relay terminal 2 - Body ground

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  6. INSPECT QUICK HEATER ASSEMBLY


    1. Remove the quick heater assembly Click here.

    2. Inspect the quick heater assembly Click here.


    NG

    REPLACE QUICK HEATER ASSEMBLY Click here

    OK

  7. CHECK HARNESS AND CONNECTOR (QUICK HEATER - BODY GROUND)


    1. B001DCGE01
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Quick Heater Assembly)

      Disconnect the G178 and G179 heater connectors.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      G178-1 (E) - Body ground Always Below 1 Ω
      G179-1 (E) - Body ground

    OK

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

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR