System Description

SYSTEM DIAGRAM 

Courtesy of NISSAN

OUTLINE 

• BCM reads the status of the combination switch (light, turn signal, wiper and washer) and recognizes the status of each switch.
• BCM has a combination of 5 output terminals (OUTPUT 1 - 5) and 5 input terminals (INPUT 1 - 5) and reads a maximum of 16 switch states.

COMBINATION SWITCH MATRIX 

Combination switch circuit

Courtesy of NISSAN

System	OUTPUT 1	OUTPUT 2	OUTPUT 3	OUTPUT 4	OUTPUT 5
INPUT 1	-	FR WASHER	FR WIPER LOW	TURN LH	TURN RH
INPUT 2	FR WIPER HI	-	FR WIPER INT	PASSING	HEADLAMP 1
INPUT 3	INT VOLUME 1	-	-	HEADLAMP 2	HI BEAM
INPUT 4	-	INT VOLUME 3	AUTO LIGHT	-	TAIL LAMP
INPUT 5	INT VOLUME 2	-	-	FR FOG	-

COMBINATION SWITCH READING FUNCTION 

Description 

• BCM reads the status of the combination switch at 10 ms intervals normally.

  Courtesy of NISSAN

  NOTE: BCM reads the status of the combination switch at 60 ms intervals when BCM is controlled at low power consumption control mode.
• BCM operates as follows and judges the status of the combination switch:
  • It operates the transistor on OUTPUT side in the following order: OUTPUT 1 -> 2 -> 3 -> 4 -> 5, and outputs voltage waveform.
  • The voltage waveform of OUTPUT corresponding to the formed circuit is input into the interface on INPUT side if any (1 or more) switches are ON.
  • It reads this change of the voltage as the status signal of the combination switch.

    Courtesy of NISSAN

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 "A - E" and OUTPUT 1 - 5 to "1 - 5".

Example 1: When a switch (TAIL LAMP) is turned ON

• The circuit between INPUT 4 and OUTPUT 5 are formed when the TAIL LAMP switch is turned ON.

  Courtesy of NISSAN

• BCM detects the combination switch status signal "5D" when the signal of INPUT 4 is input to OUTPUT 5.
• BCM judges that the TAIL LAMP switch is ON when the signal "5D" is detected.

Example 2: When some switches (TURN RH, TAIL LAMP) are turned ON

• The circuits between INPUT 1, INPUT 4 and OUTPUT 5 are formed when the TURN RH switch and TAIL LAMP switch are turned ON.

  Courtesy of NISSAN

• BCM detects the combination switch status signal "5AD" when the signals of INPUT 1 and INPUT 4 are input to OUTPUT 5.
• BCM judges that the TURN RH switch and TAIL LAMP switch are ON when the signal "5AD" 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.

Wiper intermittent dial position	Intermittent operation delay interval	INT VOLUME switch ON/OFF status
		INT VOLUME 1	INT VOLUME 2	INT VOLUME 3
1	Short↑ ↓Long	ON	ON	ON
2		ON	ON	OFF
3		ON	OFF	OFF
4		OFF	OFF	OFF
5		OFF	OFF	ON
6		OFF	ON	ON
7		OFF	ON	OFF