AIR CONDITIONING SYSTEM Power Heater Switch Circuit

DESCRIPTION

When the heater switch assembly is pushed, the air conditioning amplifier assembly outputs the engine idle up signal. If engine idle up does not occur when the heater switch assembly is pushed, there may be a problem in the circuit shown below.

WIRING DIAGRAM

B001AB2E08

PROCEDURE


  1. READ VALUE USING GTS (IDLE UP/PWR HEAT SWITCH)


    1. Use the Data List to check if the heater switch assembly is functioning properly Click here.

      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      IDLE UP/PWR HEAT Switch Heater switch assembly/ON or OFF

      ON: Heater switch assembly on

      OFF: Heater switch assembly off

      -
      OK
      The display is as specified in the normal condition column.

    NG
    OK
  2. INSPECT HEATER SWITCH ASSEMBLY


    1. Remove the heater switch assembly Click here.

    2. Inspect the heater switch assembly Click here.


    NG
    OK
  3. CHECK HARNESS AND CONNECTOR (HEATER SWITCH ASSEMBLY - AIR CONDITIONING AMPLIFIER ASSEMBLY AND BODY GROUND)


    1. Disconnect the E172 heater switch assembly connector.

    2. Disconnect the E36 air conditioning amplifier assembly connector.

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

      Tester Connection Condition Specified Condition
      E172-6 (+S) - E36-28 (SW 1) Always Below 1 Ω
      E172-3 (E) - Body ground Always Below 1 Ω
      E172-6 (+S) or E36-28 (SW 1) - Body ground Always 10 kΩ or higher

    OK
    NG