© 2001 Directed Electronics, Inc. Vista, CA
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Three-wire switches will have either a constant ground input or a constant (+)12V input, along with the
pulsed lock and unlock outputs to the factory relays.
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Many BMW’s and VW’s have no external switch. The switches are inside the actuator, and instead of pulsing,
the proper wires will flip-flop from (+)12V to (-) ground as the door locks are operated.
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Direct-wired switches will have a (+)12V constant input and one or two (-) ground inputs, along with two
output leads going directly to the lock motors.
This system is common in many Toyota, Nissan, Honda, and Saturn models, as well as Fords with the keyless-
entry system (some other Fords also use Type B).
The switch will have three wires on it, and one wire will test ground all the time. One wire will pulse (-) when
the switch locks the doors, and the other wire will pulse (-) when the switch unlocks the doors. This type of
system is difficult to mistake for any other type.
type B: negative-triggered, relay-driven system
type A: positive-triggered, relay-driven system
at the switch
