System Description

SYSTEM DIAGRAM 

Courtesy of NISSAN

OUTLINE 

• BCM reads the status of the combination and master light switches (light, turn signal, wiper and washer) and recognizes the status of each switch.
• BCM has a combination of 6 output terminals (OUTPUT 1 - 6) and 5 input terminals (INPUT 1 - 5) and reads a maximum of 20 switch states.

COMBINATION SWITCH MATRIX 

Courtesy of NISSAN

System	INPUT 1	INPUT 2	INPUT 3	INPUT 4	INPUT 5
OUTPUT 1	-	HI BEAM	PASSING	-	FR FOG
OUTPUT 2	INT VOLUME 1	-	HEADLAMP	AUTO LIGHT	TAIL LAMP
OUTPUT 3	FR WASHER	RR WASHER	-	TURN LH	TURN RH
OUTPUT 4	FR WIPER LOW	FR WIPER HI	FR WIPER INT	-	NO LIGHT
OUTPUT 5	INT VOLUME 2	INT VOLUME 3	RR WIPER INT	RR WIPER ON	-
OUTPUT 6	NO WIPER	-	-	-	-

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 → 6, 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 "1 - 5" and OUTPUT 1 - 6 to "A - F".

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

• The circuit between OUTPUT 3 and INPUT 5 is formed when the TURN RH switch is turned ON.

  Courtesy of NISSAN

• BCM detects the combination switch status signal "5C" when the signal of OUTPUT 3 is input to INPUT 5.
• BCM judges that the TURN RH switch is ON when the signal "5C" is detected.

Example 2: When some switches (FR FOG, TURN RH) are turned ON

• The circuits between OUTPUT 1 and INPUT 5 and between OUTPUT 3 and INPUT 5 are formed when the FR FOG switch and TURN RH switch are turned ON.

  Courtesy of NISSAN

• BCM detects the combination switch status signal "5AC" when the signals of OUTPUT 1 and OUTPUT 3 are input to INPUT 5.
• BCM judges that the FR FOG switch and TURN RH switch are ON when the signal "5AC" is detected.

WIPER INTERMITTENT DIAL POSITION (WITH VARIABLE INTERMITTENT WIPERS) 

BCM judges the wiper intermittent dial 1 - 7 by the status of INT VOLUME 1, 2, and 3 switches.

Wiper Intermittent Dial Position	Switch Status
	INT VOLUME 1	INT VOLUME 2	INT VOLUME 3
1	ON	OFF	OFF
2	OFF	OFF	OFF
3	OFF	ON	OFF
4	ON	ON	OFF
5	ON	ON	ON
6	ON	OFF	ON
7	OFF	OFF	ON

WIPER AUTO DIAL POSITION (WITH RAIN SENSING WIPERS) 

BCM judges the wiper auto dial 1 - 4 by the status of INT VOLUME 1, 2, and 3 switches.

Wiper Auto Dial Position	Switch Status
	INT VOLUME 1	INT VOLUME 2	INT VOLUME 3
1	ON	OFF	OFF
2	OFF	ON	OFF
3	ON	ON	ON
4	OFF	OFF	ON