Operation Table of BCM and Combination Switches

BCM reads operation status of combination switch using combinations shown in table below.

Fig 1: BCM And Combination Switches Operation Table

Sample Operation: 

• When lighting switch 1ST position is turned ON, contact in combination switch turns ON. At this time if OUTPUT 4 transistor is activated, BCM detects that voltage changes in INPUT 5.
• When OUTPUT 4 transistor is ON, BCM detects that voltage changes in INPUT 5, and judges that lighting switch 1ST position is ON. Then BCM sends tail lamp and clearance lamp request signal to IPDM E/R using CAN communication.
• When OUTPUT 4 transistor is activated again, BCM detects that voltage changes in INPUT 5, and recognizes that lighting switch 1ST position is continuously ON.
  Fig 2: Lighting Switch Circuit Diagram

  
  NOTE: Each OUTPUT terminal transistor is activated at 10 ms intervals. Therefore after switch is turned ON, electrical loads are activated with time delay. But this time delay is so short that it cannot be detected by human senses.