Combination Switch Reading Function

Description

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

  Courtesy of NISSAN MOTOR CO., U.S.A.
  NOTE: BCM reads the status of the combination switch at 60 ms 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: Identifying Combination Switch Voltage Signals 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: Identifying Combination Switch Circuit Diagram (When Switch Turned ON)

  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, 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: Identifying Combination Switch Circuit Diagram (When Some Switches Turned ON)

  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.