AIR CONDITIONING SYSTEM PTC Heater Circuit

DESCRIPTION

PTC heater relays are closed in accordance with signals from the A/C amplifier and power is supplied to the PTC heater assembly installed on the radiator heater unit.

WIRING DIAGRAM

A01CAJNE13

INSPECTION PROCEDURE

PROCEDURE


  1. INSPECT PTC HEATER RELAY (PTC NO.1)

    A01CC9WE01

    1. Remove the PTC NO. 1 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 is not applied between terminals 1 and 2 10 kΩ or higher
      3 - 5 Battery voltage is applied to terminals 1 and 2 Below 1 Ω

    NG

    REPLACE PTC HEATER RELAY

    OK

  2. INSPECT PTC HEATER RELAY (PTC NO.2)

    A01CC9WE01

    1. Remove the PTC NO. 2 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 is not applied between terminals 1 and 2 10 kΩ or higher
      3 - 5 Battery voltage is applied to terminals 1 and 2 Below 1 Ω

    NG

    REPLACE PTC HEATER RELAY

    OK

  3. INSPECT PTC HEATER RELAY (PTC NO.3)

    A01CC9WE01

    1. Remove the PTC NO .3 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 is not applied between terminals 1 and 2 10 kΩ or higher
      3 - 5 Battery voltage is applied to terminals 1 and 2 Below 1 Ω

    NG

    REPLACE PTC HEATER RELAY

    OK

  4. CHECK A/C AMPLIFIER

    A01CBNVE01

    1. Remove the A/C amplifier with its connectors still connected.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      G33-3 (PTC1) - Body ground

      Engine is running (650 rpm or higher)

      Temperature setting: MAX. HOT

      Ambient temperature: 10°C (50°F) or lower

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

      Light control switch off

      		 11 to 14 V
      G33-22 (PTC2) - Body ground
      G33-4 (PTC3) - Body ground

    NG

    CHECK HARNESS AND CONNECTOR (A/C AMPLIFIER - BODY GROUND) Click here

    OK

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

    A01CAK7E01

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

    2. Disconnect the A38 PTC heater assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      PTC NO .1 terminal 5 - A38-1 (B) Always Below 1 Ω
      PTC NO . 2 terminal 5 - A38-2 (B) Always Below 1 Ω
      PTC NO . 3 terminal 5 - A38-3 (B) Always Below 1 Ω
      PTC NO .1 terminal 5 - Body ground Always 10 kΩ or higher
      PTC NO . 2 terminal 5 - Body ground Always 10 kΩ or higher
      PTC NO . 3 terminal 5 - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  6. INSPECT PTC HEATER ASSEMBLY

    A01CELEE12

    1. Disconnect the PTC heater assembly connectors.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A38-1 (B) - A39-1 (E) Always Below 1 Ω
      A38-2 (B) - A39-1 (E) Always Below 1 Ω
      A38-3 (B) - A39-2 (E) Always Below 1 Ω

    NG

    REPLACE PTC HEATER ASSEMBLY Click here

    OK

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


    1. A01CG5HE03

      Disconnect the A39 PTC heater assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A39-1 (E) - Body ground Always Below 1 Ω
      A39-2 (E) - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  8. CHECK HARNESS AND CONNECTOR (A/C AMPLIFIER - BODY GROUND)

    A01CBTFE01

    1. Disconnect the G33 A/C amplifier connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      G33-3 (PTC1) - Body ground Always Below 1 Ω
      G33-22 (PTC2) - Body ground Always Below 1 Ω
      G33-4 (PTC3) - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE A/C AMPLIFIER Click here