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Inspection Procedure

  1. INSPECT FUSE (PS HTR, PTC HTR1, PTC HTR2, GAUGE) 
    1. Remove the PS HTR H-fuse, PTC HTR1 and PTC HTR2 fuses from the engine room junction block.
    2. Remove the GAUGE fuse from the driver side junction block.
    3. Measure the resistance of the fuses.

      Standard resistance: Below 1 Ω 

    NG : REPLACE FUSE 

    OK : GO TO NEXT STEP 

  2. INSPECT PTC HEATER RELAY (Marking: PS HTR, PTC HTR 1, PTC HTR 2) 
    1. Remove the PS HTR, PTC HTR 1 and PTC HTR 2 heater relays from the engine room No. 2 relay block.
    2. Measure the resistance of the relays.

      Standard resistance 

      TERMINALS RESISTANCE SPECIFICATIONS

      Tester Connection Specified Condition
      3 - 5 10 kΩ or higher
      3 - 5 Below 1 Ω (When battery voltage applied to terminals 1 and 2)

    NG : REPLACE PTC HEATER RELAY 

    Fig 1: Inspecting PTC Heater Relay
    G04475100Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    OK : GO TO NEXT STEP 

  3. CHECK WIRE HARNESS (AIR CONDITIONING AMPLIFIER - BATTERY) 
    1. Disconnect the A7 air conditioning amplifier connector.
    2. Measure the voltage of the wire harness side connector.

      Standard voltage 

      TERMINALS VOLTAGE SPECIFICATIONS

      Tester Connection Condition Specified Condition
      A7-17 (PTC) - Body ground Power switch ON (IG) 10 to 14 V
      A7-26 (HT-1) - Body ground Power switch ON (IG) 10 to 14 V
      A7-25 (HT-2) - Body ground Power switch ON (IG) 10 to 14 V

    NG : REPAIR OR REPLACE HARNESS AND CONNECTOR 

    Fig 2: Disconnecting A7 Air Conditioning Amplifier Connector
    G04475101Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    OK : GO TO NEXT STEP 

  4. CHECK AIR CONDITIONING AMPLIFIER (PTC, HT-1, HT-2, VOLTAGE) 
    1. Connect the connectors.
    2. Measure the voltage of the connector.

      Standard voltage 

      TERMINALS VOLTAGE SPECIFICATIONS

      Tester Connection Condition Specified Condition
      A7-17 (PTC) - Body ground Power switch ON (READY)
      Temperature: Max. HOT
      Ventilator mode: FOOT
      Coolant temperature:
      55°C (131°F) or lower
      Blower switch: OFF --> LO (after 30 sec.)      		 Below 1 V --> 10 to 14 V
      A7-26 (HT-1) - Body ground Power switch ON (READY)
      Temperature: Max. HOT
      Ventilator mode: FOOT
      Coolant temperature:
      55°C (131°F) or lower
      Blower switch: OFF --> LO (after 30 sec.)      		 Below 1 V --> 10 to 14 V
      A7-25 (HT-2) - Body ground Power switch ON (READY)
      Temperature: Max. HOT
      Ventilator mode: FOOT
      Coolant temperature:
      55°C (131°F) or lower
      Blower switch: OFF --> LO (after 30 sec.)      		 Below 1 V --> 10 to 14 V

      HINT:

      • PTC operation may stop when the electric load on the vehicle is high. Perform the inspection under conditions with low electric load (such as with headlights turned OFF).
      • Since the 2 PTC heaters are gradually turned to the ON position, perform the inspection 30 seconds after the blower switch is turned to the LO position.
        Fig 3: Identifying Air Conditioning Amplifier Connectors
        G04475102Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG : REPLACE AIR CONDITIONING AMPLIFIER 

    OK : GO TO NEXT STEP 

  5. INSPECT PTC HEATER 
    1. Disconnect the connector from the PTC heater.
    2. Check the continuity between each terminal.

      Standard resistance 

      TERMINALS RESISTANCE SPECIFICATIONS

      Tester Connection Specified Condition
      P12-1 - P12-2 Continuity (0.5 kΩ or higher)
      P12-3 - P12-4 Continuity (0.5 kΩ or higher)

    NG : REPLACE PTC HEATER 

    Fig 4: Identifying PTC Heater Connector
    G04475103Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    OK : REPAIR OR REPLACE HARNESS AND CONNECTOR 

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