AIR CONDITIONING SYSTEM PTC Heater Circuit

DESCRIPTION

The PTC heater assembly is installed in the heater radiator 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 number of circuits operated in the PTC heater is controlled according to the overall electric load of the vehicle and charging system output (DC-DC converter built into inverter with converter assembly). therefore, troubleshooting should be performed with other electrical components turned off.

WIRING DIAGRAM

A004X86E09

PROCEDURE


  1. INSPECT PTC HEATER ASSEMBLY


    1. A004ZW7E03
      Text in Illustration
      *a

      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
      A17-3 (B) - A18-2 (E) Always Below 1 Ω
      A17-2 (B) - A18-2 (E) Always Below 1 Ω
      A17-2 (B) - A18-1 (E) Always Below 1 Ω
      A17-1 (B) - A18-1 (E) Always Below 1 Ω

    NG

    REPLACE PTC HEATER ASSEMBLY Click here

    OK

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


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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A18-1 (E) - Body ground Always Below 1 Ω
      A18-2 (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 PTC heater assembly connector.

    2. Disconnect the 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
      A17-1 (B) - 1H-10 (PTC1) Always Below 1 Ω
      A17-2 (B) - 1H-6 (PTC2) Always Below 1 Ω
      A17-3 (B) - 1H-9 (PTC3) Always Below 1 Ω
      A17-1 (B) - Body ground Always 10 kΩ or higher
      A17-2 (B) - Body ground Always 10 kΩ or higher
      A17-3 (B) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER - NO. 1 INTEGRATION RELAY)


    1. Disconnect the air conditioning amplifier assembly connector.

    2. Disconnect the 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
      H85-18 (PTC1) - 1G-17 (PTCA) Always Below 1 Ω
      H85-38 (PTC2) - 1G-26 (PTCB) Always Below 1 Ω
      H85-16 (PTC3) - 1G-25 (PTCC) Always Below 1 Ω
      H85-18 (PTC1) - Body ground Always 10 kΩ or higher
      H85-38 (PTC2) - Body ground Always 10 kΩ or higher
      H85-16 (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.

    OK

    END (NO. 1 INTEGRATION RELAY WAS DEFECTIVE)

    NG

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