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

A01X0RLE04

PROCEDURE


  1. INSPECT PTC HEATER RELAY (PTC HTR1)

    A01X1FLE08
    *a PTC HTR1 Relay

    1. Remove the PTC HTR1 relay from the engine room 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 not applied between terminals 1 and 2 10 kΩ or higher
      Battery voltage applied to terminals 1 and 2 Below 1 Ω

    NG

    REPLACE PTC HEATER RELAY

    OK

  2. INSPECT PTC HEATER RELAY (PTC HTR2)

    A01X1FLE09
    *a PTC HTR2 Relay

    1. Remove the PTC HTR2 relay from the engine room 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 not applied between terminals 1 and 2 10 kΩ or higher
      Battery voltage applied to terminals 1 and 2 Below 1 Ω

    NG

    REPLACE PTC HEATER RELAY

    OK

  3. INSPECT PTC HEATER RELAY (PTC HTR3)

    A01X1FLE10
    *a PTC HTR3 Relay

    1. Remove the PTC HTR3 relay from the engine room 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 not applied between terminals 1 and 2 10 kΩ or higher
      Battery voltage applied to terminals 1 and 2 Below 1 Ω

    NG

    REPLACE PTC HEATER RELAY

    OK

  4. CHECK AIR CONDITIONING AMPLIFIER ASSEMBLY

    A01X71ME02
    *1 Component with harness connected: (Air Conditioning Amplifier Assembly)

    1. w/ Rear Heater


      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
        E36-27 (PTC1) - Body ground

        Engine switch on (IG)

        Temperature setting: MAX, HOT

        MODE switch: FOOT

        Engine coolant temperature: 55°C (131°F) or less

        Blower switch: off

        		 11 to 14 V
        E36-26 (PTC2) - Body ground
        E36-35 (PTC3) - Body ground
    2. A01X09TE01
      *1 Component with harness connected: (Air Conditioning Amplifier Assembly)

      w/o Rear Heater


      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
        E81-3 (PTC1) - Body ground

        Engine switch on (IG)

        Temperature setting: MAX, HOT

        MODE switch: FOOT

        Engine coolant temperature: 55°C (131°F) or less

        Blower switch: off

        		 11 to 14 V
        E81-22 (PTC2) - Body ground
        E81-4 (PTC3) - Body ground

    NG

    CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER - PTC HTR RELAY) Click here

    OK

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

    A01X7IHE01
    Engine Room Relay Block
    *1 Front view of wire harness connector: (to Quick Heater Assembly)
    *2 PTC HTR3 Relay
    *3 PTC HTR1 Relay

    1. Remove the quick heater relays from the engine room relay block.

    2. Disconnect the E33 quick heater assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      PTC HTR2 terminal 3 - E33-1 (B) Always Below 1 Ω
      PTC HTR1 terminal 3 - E33-2 (B)
      PTC HTR3 terminal 3 - E33-3 (B)
      PTC HTR2 terminal 3 - Body ground Always 10 kΩ or higher
      PTC HTR1 terminal 3 - Body ground
      PTC HTR3 terminal 3 - Body ground

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  6. INSPECT QUICK HEATER ASSEMBLY

    A01XBV5E02
    *1 Component without harness connected: (Quick Heater Assembly)

    1. Disconnect the E33 and E34 quick heater connectors.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      E33-1 (B) - E34-1 (E) Always Below 1 Ω
      E33-2 (B) - E34-1 (E)
      E33-3 (B) - E34-2 (E)

    NG

    REPLACE QUICK HEATER RELAY Click here

    OK

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


    1. A01X2N8E01
      *1 Front view of wire harness connector: (to Quick Heater Assembly)

      Disconnect the E34 quick heater assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      E34-1 (E) - Body ground Always 10 kΩ or higher
      E34-2 (E) - Body ground

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  8. CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER - PTC HTR RELAY)

    A01X7O6E01
    *1 Rear view of wire harness connector: (to Air Conditioning Amplifier Assembly)

    1. w/ Rear Heater


      1. Disconnect the E36 amplifier connector.

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

        Standard Resistance
        Tester Connection Condition Specified Condition
        E36-27 (PTC1) - Body ground Always Below 1 Ω
        E36-26 (PTC2) - Body ground
        E36-35 (PTC3) - Body ground
    2. A01X67VE01
      *1 Rear view of wire harness connector: (to Air Conditioning Amplifier Assembly)

      w/o Rear Heater


      1. Disconnect the E81 amplifier connector.

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

        Standard Resistance
        Tester Connection Condition Specified Condition
        E81-3 (PTC1) - Body ground Always Below 1 Ω
        E81-22 (PTC2) - Body ground
        E81-4 (PTC3) - Body ground
        Result
        Result Proceed to
        OK (for LHD) A
        OK (for RHD) B
        NG C

    OK

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR