B737NG oil differential pressure switch

[subu008]

i have some questions on oil differential pressure switch
the switch has three pins 。pin 1 and pin 2 named SW 1，pin 3 and pin 2 named SW2。
in the CDU ----MAINT---ENGINE ---INPUT MONITORING---OIL SYSTEM
there are SW1 CH A，SW1 CHB。
who can tell me how CHA and CHB come true？the SSM 79-33-11 has no more information abort CHA and CHB of the oil differential pressure switch how to come true in EEC

[Wmn]

I can't figure out what answer you are looking for?

This is the normal logic(other states can be found);

SW1 CHA & CHB CLOSED and SW2 CHA & CHB OPEN = "not clogged"
SW1 CHA & CHB OPEN and SW2 CHA & CHB CLOSED = "clogged"

Seems like the two switches sends their respective signals to BOTH EEC channels and for this you only need three pins.