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

A01DTZ2E02

INSPECTION PROCEDURE

PROCEDURE


  1. INSPECT PTC HEATER RELAY (PTC NO. 1, PTC NO. 2, PTC NO. 3)


    1. A01DT9H

      Remove the PTC NO. 1, PTC NO. 2 and PTC NO. 3 relays from the engine room No. 2 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, PTC NO. 2, PTC NO. 3)

    OK

  2. CHECK AIR CONDITIONING AMPLIFIER ASSEMBLY


    1. A01DTIYE10
      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

      		 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 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

      		 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 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

      Tech Tips

      *: After the measurement conditions are met, wait 30 seconds before performing measurements.


    NG

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

    OK

  3. CHECK HARNESS AND CONNECTOR (ENGINE ROOM NO. 2 RELAY BLOCK - AIR CONDITIONING AMPLIFIER)


    1. Remove the PTC heater relays from the engine room No. 2 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 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 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. 2 RELAY BLOCK - QUICK HEATER)


    1. Remove the PTC heater relays from the engine room No. 2 relay block.

    2. Disconnect the G28 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 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 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. 2 RELAY BLOCK - BATTERY AND BODY GROUND)


    1. A01DOFCE02
      Text in Illustration
      *1 PTC NO. 1 Relay
      *2 PTC NO. 2 Relay
      *3 PTC NO. 3 Relay
      *a

      Component without relay installed

      (Engine Room No. 2 Relay Block)

      Remove the PTC heater relays from the engine room No. 2 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 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 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. A01DS97E08

      Remove the quick heater assembly Click here.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      1 (B) - 1 (E) Always Below 1 kΩ
      2 (B) - 1 (E)
      2 (B) - 2 (E)
      3 (B) - 2 (E)

    NG

    REPLACE QUICK HEATER ASSEMBLY Click here

    OK

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


    1. A01DNE4E10
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Quick Heater Assembly)

      Disconnect the G29 heater connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      G29-1 (E) - Body ground Always Below 1 Ω
      G29-2 (E) - Body ground

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

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