AIR CONDITIONING SYSTEM PTC Heater Circuit

DESCRIPTION

The PTC heater assembly is installed in the radiator in the heater unit and operates when engine coolant temperature is low and normal heater effectiveness is insufficient.

The A/C control assembly switches the circuit in the PTC relay and operates the PTC heater assembly when the operating conditions (cooling water temperature is below 65°C (149°F), setting temperature is MAX. HOT, ambient temperature is below 10°C (50°F) and blower switch is not OFF) are met.

The PTC heater assembly controls PTC heater lines by electric load or the amount of inverter with converter assembly (PCU) output. Therefore, troubleshooting should be performed with other electric components off.

WIRING DIAGRAM

A003U0DE05

INSPECTION PROCEDURE

PROCEDURE


  1. INSPECT PTC HEATER ASSEMBLY


    1. A003S53E17
      Text in Illustration
      *1

      Component without harness connected

      (PTC Heater Assembly)

      Remove the PTC heater assembly.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A14-1 (B) - A15-1 (E) Always Below 1 Ω
      A14-2 (B) - A15-2 (E) Always Below 1 Ω
      A14-2 (B) - A15-1 (E) Always Below 1 Ω
      A14-3 (B) - A15-2 (E) Always Below 1 Ω

    NG

    REPLACE PTC HEATER ASSEMBLY Click here

    OK

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


    1. A003TEFE03
      Text in Illustration
      *1

      Front view of wire harness connector

      (to PTC Heater Assembly)

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A15-1 (E) - Body ground Always Below 1 Ω
      A15-2 (E) - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  3. CHECK HARNESS AND CONNECTOR (PTC HEATER ASSEMBLY - NO. 1 INTEGRATION RELAY)


    1. Disconnect the A14 PTC heater assembly connector.

    2. Disconnect the 1H engine room relay block and junction block (NO. 1 integration relay) connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A14-1 (B) - 1H-10 (PTC1) Always Below 1 Ω
      A14-2 (B) - 1H-6 (PTC2) Always Below 1 Ω
      A14-3 (B) - 1H-9 (PTC3) Always Below 1 Ω
      A14-1 (B) - Body ground Always 10 kΩ or higher
      A14-2 (B) - Body ground Always 10 kΩ or higher
      A14-3 (B) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. CHECK HARNESS AND CONNECTOR (A/C AMPLIFIER - NO. 1 INTEGRATION RELAY)


    1. Disconnect the E30 A/C amplifier connector.

    2. Disconnect the 1G engine room relay block and junction block (NO. 1 integration relay) connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      E30-18 (PTC1) - 1G-17 (PTCA) Always Below 1 Ω
      E30-38 (PTC2) - 1G-26 (PTCB) Always Below 1 Ω
      E30-16 (PTC3) - 1G-25 (PTCC) Always Below 1 Ω
      E30-18 (PTC1) - Body ground Always 10 kΩ or higher
      E30-38 (PTC2) - Body ground Always 10 kΩ or higher
      E30-16 (PTC3) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  5. REPLACE NO. 1 INTEGRATION RELAY


    1. Replace the NO. 1 integration relay Click here.

      Tech Tips

      Since the NO. 1 integration relay cannot be inspected while it is removed from the vehicle, replace the NO. 1 integration relay with a new or a known good one and check that the condition returns to normal.

    2. Check if the same problem occurs again.

      OK
      Same problem does not occur.

    NG

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

    OK

    END (NO. 1 INTEGRATION RELAY WAS DEFECTIVE)