AIR CONDITIONING SYSTEM(for Manual 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

A004TREE06

PROCEDURE


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

    A004MK6

    1. Remove the HTR SUB NO.1, HTR SUB NO.2 and HTR SUB 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 (HTR SUB NO.1, HTR SUB NO.2, HTR SUB NO.3)

    OK

  2. CHECK AIR CONDITIONING AMPLIFIER ASSEMBLY

    A004NDRE01
    Text in Illustration
    *1

    Component with harness connected

    (Air Conditioning Amplifier Assembly)

    1. 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
      D101-40 (PTC1) - Body ground

      • Engine running (1250 rpm or more)

      • Temperature setting: MAX. HOT

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

      • Engine coolant temperature: 75°C (167°F) or less

      • Headlight dimmer switch: off

      • Blower switch: off

      		 11 to 14 V*
      D101-3 (PTC2) - Body ground

      • Engine running (1250 rpm or more)

      • Temperature setting: MAX. HOT

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

      • Engine coolant temperature: 70°C (158°F)

      • Headlight dimmer switch: off

      • Blower switch: off
      D101-39 (PTC3) - Body ground

      • Engine running (1250 rpm or more)

      • Temperature setting: MAX. HOT

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

      • Engine coolant temperature: 65°C (149°F) or less

      • Headlight dimmer switch: off

      • Blower switch: off
      D101-40 (PTC1) - Body ground

      • Engine running (1250 rpm or more)

      • Temperature setting: MAX. HOT

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

      • Engine coolant temperature: 75°C (167°F) or less

      • Headlight dimmer switch: off

      • Blower switch: on

      		 Below 1 V*
      D101-3 (PTC2) - Body ground

      • Engine running (1250 rpm or more)

      • Temperature setting: MAX. HOT

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

      • Engine coolant temperature: 70°C (158°F)

      • Headlight dimmer switch: off

      • Blower switch: on
      D101-39 (PTC3) - Body ground

      • Engine running (1250 rpm or more)

      • Temperature setting: MAX. HOT

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

      • Engine coolant temperature: 65°C (149°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

    CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER - BODY GROUND) Click here

    OK

  3. CHECK HARNESS AND CONNECTOR (PTC HEATER RELAY - QUICK HEATER)

    A004UCHE01
    Text in Illustration
    *1

    Component without relay installed

    (Engine Room No. 2 Relay Block)
    *2

    Front view of wire harness connector

    (to Quick Heater Assembly)

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

    2. Disconnect the A44 quick heater assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      HTR SUB NO.1 relay terminal 5 - A44-2 (B) Always Below 1 Ω
      HTR SUB NO.2 relay terminal 5 - A44-1 (B)
      HTR SUB NO.3 relay terminal 5 - A44-3 (B)
      HTR SUB NO.1 relay terminal 5 - Body ground Always 10 kΩ or higher
      HTR SUB NO.2 relay terminal 5 - Body ground
      HTR SUB NO.3 relay terminal 5 - Body ground

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. INSPECT QUICK HEATER ASSEMBLY

    A004PNZE06
    Text in Illustration
    *1

    Component without harness connected

    (Quick Heater Assembly)

    1. Disconnect the quick heater assembly connectors.

    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

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


    1. A004O5BE01
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Quick Heater Assembly)

      Disconnect the A45 quick heater assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A45-1 (E) - Body ground Always Below 1 Ω
      A45-2 (E) - Body ground

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  6. CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER - BODY GROUND)

    A004SQ2E01
    Text in Illustration
    *1

    Rear view of wire harness connector

    (to Air Conditioning Amplifier Assembly)

    1. Disconnect the D101 amplifier connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      D101-40 (PTC1) - Body ground Always Below 200 Ω
      D101-3 (PTC2) - Body ground
      D101-39 (PTC3) - Body ground

    OK

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

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR