AUDIO AND VISUAL SYSTEM (w/o Multi-display) Dimmer Signal Circuit

DESCRIPTION

The radio receiver assembly uses this circuit to communicate with the main body ECU (multiplex network body ECU) via a direct line. The main body ECU (multiplex network body ECU) uses this circuit to send an auto dimmer signal to the radio receiver assembly. The main body ECU (multiplex network body ECU) detects the position of the light control switch according to the resistance. When the light control switch is set to the head or tail position, the resistance between the head or tail terminal and body ground is below 1Ω. When the light control switch is set to the head or tail position, the main body ECU (multiplex network body ECU) sends an auto dimmer signal to the radio receiver assembly. When the radio receiver assembly receives an auto dimmer signal from the main body ECU (multiplex network body ECU), the radio receiver assembly causes the instrument panel illumination to be dimmed.

WIRING DIAGRAM

A01G97RE01

INSPECTION PROCEDURE

Note

If the main body ECU (multiplex network body ECU) is replaced, refer to Service Bulletin.

PROCEDURE


  1. CHECK MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)


    1. Disconnect the H83 radio receiver assembly connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      H83-20 (ADIM) - Body ground Engine switch on (IG), automatic light control sensor covered by hand, and light control switch in the tail or head position 11 to 14 V

    NG

    CHECK HARNESS AND CONNECTOR (RADIO RECEIVER ASSEMBLY - INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY) Click here

    OK

    REPLACE RADIO RECEIVER ASSEMBLY Click here

  2. CHECK HARNESS AND CONNECTOR (RADIO RECEIVER ASSEMBLY - INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY)


    1. Disconnect the H83 radio receiver assembly connector.

    2. Disconnect the 3B instrument panel junction block assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      3B-38 - H83-20 (ADIM) Always Below 1 Ω
      H83-20 (ADIM) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  3. INSPECT INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY


    1. Remove the instrument panel junction block assembly Click here.

    2. Remove the main body ECU (multiplex network body ECU) from the instrument panel junction block assembly.

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

      A01G4NAE09
      Standard Resistance
      Tester Connection Condition Specified Condition
      3B-38 - MB-23 (ACAN) Always Below 1 Ω
      Text in Illustration
      *a

      Component without harness connected

      (Instrument Panel Junction Block Assembly)

      		 - -

    NG

    REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY Click here

    OK

    REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) Click here