AIR CONDITIONING SYSTEM(for Manual Air Conditioning System) Heater Control Switch Circuit

DTC Code DTC Name
Heater Control Switch Circuit

DESCRIPTION

The No. 3 heater control sub-assembly is powered through the HTR-IG fuse. The No. 3 heater control sub-assembly transmits the operation signals of each switch to the air conditioning amplifier.

WIRING DIAGRAM

E290761E03

CAUTION / NOTICE / HINT

Note:

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

PROCEDURE

  1. INSPECT NO. 3 HEATER CONTROL SUB-ASSEMBLY

    1. E185650E01

      Remove the No. 3 heater control sub-assembly (Click here).

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

      Standard Resistance

      Tester Connection

      Switch Condition

      Specified Condition

      2 (B) - 3 (A/C)

      A/C switch on

      Below 1 Ω

      2 (B) - 3 (A/C)

      A/C switch off

      10 kΩ or higher

      7 (B) - 8 (E)*

      Temperature setting MAX HOT

      Below 1 Ω

      7 (B) - 8 (E)*

      Temperature setting not MAX HOT

      10 kΩ or higher

      • *: w/ PTC heater

    3. Apply battery voltage to the No. 3 heater control sub-assembly and check that the indicator light comes on.

      OK

      Measurement Condition

      Specified Condition

      Battery positive (+) → Terminal 3

      Battery negative (-) → Terminal 4

      Indicator light comes on
      Table 1. Text in Illustration

      *1

      w/ PTC Heater

    REPLACE NO. 3 HEATER CONTROL SUB-ASSEMBLY

    (Click here)

  2. CHECK HARNESS AND CONNECTOR (NO. 3 HEATER CONTROL - BATTERY)

    1. U123639E02

      Disconnect the H23 heater control connector.

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

      Standard Voltage

      Tester Connection

      Switch Condition

      Specified condition

      H23-2 (B) - Body ground

      Ignition switch ON

      11 to 14 V

      H23-2 (B) - Body ground

      Ignition switch off

      Below 1 V

      H23-7 (B) - Body ground*

      Ignition switch ON

      11 to 14 V

      H23-7 (B) - Body ground*

      Ignition switch off

      Below 1 V

      • *: w/ PTC heater

      Table 2. Text in Illustration

      *1

      Front view of wire harness connector

      (to No. 3 Heater Control Sub-assembly)

      *2

      w/ PTC Heater

    REPAIR OR REPLACE HARNESS OR CONNECTOR

  3. CHECK HARNESS AND CONNECTOR (NO. 3 HEATER CONTROL - AIR CONDITIONING AMPLIFIER)

    1. U124099E02

      Disconnect the H118 amplifier connector.

    2. Disconnect the H23 heater control connector.

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

      Standard Resistance

      Tester Connection

      Condition

      Specified condition

      H23-3 (A/C) - H118-2 (A/C)

      Always

      Below 1 Ω

      H23-4 (AIND) - H118-16 (LED)

      Always

      Below 1 Ω

      H23-8 (E) - H118-3 (HEAT)*

      Always

      Below 1 Ω

      H23-3 (A/C) - Body ground

      Always

      10 kΩ or higher

      H23-4 (AIND) - Body ground

      Always

      10 kΩ or higher

      H23-8 (E) - Body ground*

      Always

      10 kΩ or higher

      • *: w/ PTC heater

      Table 3. Text in Illustration

      *1

      Front view of wire harness connector

      (to Air Conditioning Amplifier Assembly)

      *2

      Front view of wire harness connector

      (to No. 3 Heater Control Sub-assembly)

      *3

      w/ PTC Heater

    PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

    (Click here)

    REPAIR OR REPLACE HARNESS OR CONNECTOR