Directed Electronics G312R Owner's Installation Manual page 32

Locate the suspected lock wire, and with the red meter lead still
secured to a (+)12 volt source, probe the suspect wire with the
black lead of the meter. Press the door lock switch to the lock
position and watch the meter display. The correct wire will show
a 10.00 to 12.00 volt pulse when the switch is pressed.
note: Additional parts may be required to interface with
certain door lock types.
The Rattler Do-It-Yourself system comes with on board relays.
© 2003 directed electronics, inc. 29