AUDIO AND VISUAL SYSTEM Microphone Circuit between Microphone and Radio Receiver

DESCRIPTION

• The radio and display receiver assembly and map light assembly (telephone microphone assembly) are connected to each other using the microphone connection detection signal lines.

• Using this circuit, the radio and display receiver assembly sends power to the map light assembly (telephone microphone assembly), and the map light assembly (telephone microphone assembly) sends microphone signals to the radio and display receiver assembly.

WIRING DIAGRAM

*a	(Shielded)
*b	Map Light Assembly (Telephone Microphone Assembly)
*c	Radio and Display Receiver Assembly

PROCEDURE

1. CHECK HARNESS AND CONNECTOR (RADIO AND DISPLAY RECEIVER ASSEMBLY - MAP LIGHT ASSEMBLY (TELEPHONE MICROPHONE ASSEMBLY))

   
   

   1. Disconnect the L35 radio and display receiver assembly connector.

   2. Disconnect the U3 map light assembly (telephone microphone assembly) connector.

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

      Standard Resistance

      Tester Connection Condition Specified Condition L35-6 (SNS2) - U3-5 (SNS2) Always Below 1 Ω L35-4 (MACC) - U3-2 (MACC) Always Below 1 Ω L35-5 (MIN+) - U3-3 (MCO+) Always Below 1 Ω L35-19 (MIN-) - U3-4 (MCO-) Always Below 1 Ω L35-6 (SNS2) - Body ground Always 10 kΩ or higher L35-4 (MACC) - Body ground Always 10 kΩ or higher L35-5 (MIN+) - Body ground Always 10 kΩ or higher L35-19 (MIN-) - Body ground Always 10 kΩ or higher L35-18 (SGND) - Body ground Always 10 kΩ or higher

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR

   OK

2. INSPECT RADIO AND DISPLAY RECEIVER ASSEMBLY

   
   

   1. Reconnect the L35 radio and display receiver assembly connector.

   2. Reconnect the U3 map light assembly (telephone microphone assembly) connector.

   3. 

      Text in Illustration

      *a	Component with harness connected (Radio and Display Receiver Assembly)

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

      Standard Voltage
      Tester Connection Condition Specified Condition L35-4 (MACC) - Body ground Power switch on (ACC) 4 to 6 V

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

      Standard Resistance
      Tester Connection Condition Specified Condition L35-18 (SGND) - Body ground Always Below 1 Ω L35-19 (MIN-) - Body ground Always Below 1 Ω

   
   

   NG

   REPLACE RADIO AND DISPLAY RECEIVER ASSEMBLY Click here

   OK

3. INSPECT MAP LIGHT ASSEMBLY (TELEPHONE MICROPHONE ASSEMBLY)

   
   

   1. Disconnect the U3 map light assembly (telephone microphone assembly) connector.

   2. 

      Text in Illustration

      *a	Component without harness connected (Map Light Assembly (Telephone Microphone Assembly))

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

      Standard Resistance
      Tester Connection Condition Specified Condition U3-5 (SNS2) - U3-4 (MCO-) Always Below 1 Ω

   
   

   NG

   REPLACE TELEPHONE MICROPHONE ASSEMBLY Click here

   OK

4. INSPECT MAP LIGHT ASSEMBLY (TELEPHONE MICROPHONE ASSEMBLY)

   
   

   1. Reconnect the L35 radio and display receiver assembly connector.

   2. Reconnect the U3 map light assembly (telephone microphone assembly) connector.

   3. Turn the power switch on (ACC).

   4. Connect an oscilloscope to terminals 3 (MCO+) and 4 (MCO-) of the U3 map light assembly (telephone microphone assembly) connector.

   5. 

      Text in Illustration

      *a	Component with harness connected (Map Light Assembly (Telephone Microphone Assembly))

      Check the waveform of the telephone microphone assembly using the oscilloscope.

      Result
      Result Proceed to A waveform synchronized with the voice input to the map light assembly (telephone microphone assembly) is output A A waveform synchronized with the voice input to the map light assembly (telephone microphone assembly) is not output B

   
   

   A

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

   B

5. REPLACE TELEPHONE MICROPHONE ASSEMBLY

   
   

   1. Replace the telephone microphone assembly Click here.

   2. Check if the same malfunction recurs.

      Result
      Result Proceed to Malfunction does not recur (returns to normal) A Malfunction recurs B

   
   

   A

   END

   B

   REPLACE MAP LIGHT ASSEMBLY Click here