2005 Nissan-Datsun Altima SE-R, AutomaticFACTORY OEM SERVICE PROCEDURE

Combination Switch Reading Function

  1. Description
    • BCM reads combination switch (light, wiper) status, and controls various electrical components according to the results.
    • BCM reads information of a maximum of 20 switches by combining five output terminals (OUTPUT 1-5) and five input terminals (INPUT 1-5).
  2. Operation description
    • BCM activates transistors of output terminals (OUTPUT 1-5) periodically and allows current to flow in turn.
    • If any (1 or more) of the switches are turned ON, circuit of output terminals (OUTPUT 1-5) and input terminals (INPUT 1-5) becomes active.
    • At this time, transistors of output terminals (OUTPUT 1-5) are activated to allow current to flow. When voltage of input terminals (INPUT 1-5) corresponding to that switch changes, interface in BCM detects voltage change and BCM determines that switch is ON.
      Fig 1: Circuit Diagram - Combination Switch
      G02524362Courtesy of NISSAN MOTOR CO., U.S.A.
  3. BCM - Operation table of combination switch.
    • BCM reads operation status of combination switch by the combination shown in the following table.
      Fig 2: Combination Switch Operation Table (BCM)
      G02524363Courtesy of NISSAN MOTOR CO., U.S.A.
    NOTE: Headlamp has a dual system switch.
  4. Example operation: (When lighting switch 1st position turned ON)
    • When lighting switch 1st position is 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 lighting switch 1st position is ON. Then BCM sends tail lamp ON 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 3: Circuit Diagram - Combination Switch
      G02524364Courtesy of NISSAN MOTOR CO., U.S.A.
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