Combination Switch Reading Function

Description 

• BCM reads the status of the combination switch at 10ms interval normally.
  Fig 1: Identifying Combination Switch Reading

  Courtesy of NISSAN MOTOR CO., U.S.A.
  NOTE: BCM reads the status of the combination switch at 60ms interval when BCM is controlled at low power consumption mode.
• BCM operates as follows and judges the status of the combination switch.
  • INPUT 1 - 5 outputs the voltage waveforms of 5 systems simultaneously.
  • It operates the transistor on OUTPUT side in the following order: OUTPUT 5 → 4 →3 →2 →1.
  • The voltage waveform of INPUT corresponding to the formed circuit changes according to the operation of the transistor on OUTPUT side if any (1 or more) switches are ON.
  • It reads this change of the voltage as the status signal of the combination switch.
    Fig 2: Combination Switch Output Voltage Graph

    Courtesy of NISSAN MOTOR CO., U.S.A.

Operation Example 

In the following operation example, the combination of the status signals of the combination switch is replaced as follows: INPUT 1 - 5 to "1 - 5" and OUTPUT 1 - 5 to "A - E".

Example 1: When a switch (TURN RH switch) is turned ON

• The circuit between INPUT 1 and OUTPUT 5 is formed when the TURN RH switch is turned ON.
  Fig 3: Combination Switch - Circuit Diagram (Example 1)

  Courtesy of NISSAN MOTOR CO., U.S.A.
• BCM detects the combination switch status signal "1E" when the signal of OUTPUT 5 is input to INPUT 1.
• BCM judges that the TURN RH switch is ON when the signal "1E" is detected.
• Example 2: When some switches (TURN RH switch, FR WIPER LOW switch) are turned ON

  Example 2: When some switches (turn RH switch, front wiper LO switch) are turned ON

• The circuits between INPUT 1 and OUTPUT 5 and between INPUT 1 and OUTPUT 3 are formed when the TURN RH switch and FR WIPER LOW switch are turned ON.
  Fig 4: Combination Switch - Circuit Diagram (Example 2)

  Courtesy of NISSAN MOTOR CO., U.S.A.
• BCM detects the combination switch status signal "1CE" when the signals of OUTPUT 3 and OUTPUT 5 are input to INPUT 1.
• BCM judges that the TURN RH switch and FR WIPER LOW switch are ON when the signal "1CE" is detected.

WIPER INTERMITTENT DIAL POSITION SETTING (FRONT WIPER INTERMITTENT OPERATION) BCM judges the wiper intermittent dial 1 - 7 by the status of INT VOLUME 1, 2, and 3 switches.