Combination Switch Reading Function

Description

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

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

• 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: Voltage Input/Output Signal Operation

  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

  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: Combination Switch Circuit Diagram

  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.