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

A0159T8E16

INSPECTION PROCEDURE

Note

Inspect the fuses and relays for circuits related to this system before performing the following inspection procedure.

PROCEDURE


  1. INSPECT PTC HEATER RELAY (PTC HTR1, PTC HTR2, PTC HTR3)


    1. A015BNFE05

      Remove the PTC heater relays from the engine room relay block and junction block assembly.

    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
      Battery voltage is applied between terminals 1 and 2 Below 1 Ω

    NG

    REPLACE PTC HEATER RELAY (PTC HTR1, PTC HTR2, PTC HTR3)

    OK

  2. CHECK HARNESS AND CONNECTOR (PTC HEATER RELAY - BATTERY)


    1. A015C9KE01
      Text in Illustration
      *a

      Component without relay installed

      (Engine Room Relay Block and Junction Block Assembly)
      *1 PTC Heater Relay (PTC HTR3)
      *2 PTC Heater Relay (PTC HTR2)
      *3 PTC Heater Relay (PTC HTR1)

      Remove the PTC heater relays from the engine room relay block and junction block assembly.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      PTC HTR1 relay terminal 5 - Body ground Always 11 to 14 V
      PTC HTR2 relay terminal 5 - Body ground
      PTC HTR3 relay terminal 5 - Body ground

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  3. CHECK HARNESS AND CONNECTOR (PTC HEATER RELAY - AIR CONDITIONING AMPLIFIER AND BODY GROUND)


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

    2. Disconnect the E81 air conditioning amplifier assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      PTC HTR1 relay terminal 1 - E81-3 (PTC1) Always Below 1 Ω
      PTC HTR2 relay terminal 1 - E81-22 (PTC2)
      PTC HTR3 relay terminal 1 - E81-4 (PTC3)
      PTC HTR1 relay terminal 1 - Body ground Always 10 kΩ or higher
      PTC HTR2 relay terminal 1 - Body ground
      PTC HTR3 relay terminal 1 - Body ground

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      PTC HTR1 relay terminal 2 - Body ground Always Below 1 Ω
      PTC HTR2 relay terminal 2 - Body ground
      PTC HTR3 relay terminal 2 - Body ground

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

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


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

    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 HTR1 relay terminal 3 - E33-2 (B) Always Below 1 Ω
      PTC HTR2 relay terminal 3 - E33-1 (B)
      PTC HTR3 relay terminal 3 - E33-3 (B)
      PTC HTR1 relay terminal 3 - Body ground Always 10 kΩ or higher
      PTC HTR2 relay terminal 3 - Body ground
      PTC HTR3 relay terminal 3 - Body ground

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

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


    1. A015BE6E13
      Text in Illustration
      *a

      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 Below 1 Ω
      E34-2 (E) - Body ground

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  6. INSPECT QUICK HEATER ASSEMBLY


    1. A015BNUE08

      Remove the quick heater assembly Click here.

    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

  7. CHECK AIR CONDITIONING AMPLIFIER ASSEMBLY


    1. A0156F4E14
      Text in Illustration
      *a

      Component with harness connected

      (Air Conditioning Amplifier Assembly)

      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 idling

      Set temperature MAX. HOT

      Engine coolant temperature below 65°C (149°F)

      Ambient temperature below 10°C (50°F)

      Blower switch off → LO level

      		 Below 1 V → 11 to 14 V*
      E81-22 (PTC2) - Body ground
      E81-4 (PTC3) - Body ground

      Tech Tips

      *: After the measurement conditions are met, wait 30 seconds before performing measurements.


    NG

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Click here

    OK

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