Installing a Security System on a 1999 Dodge Caravan

Hey, I was wondering if anyone know how to wire the unlock and lock wires, with a single wire system. I've seen some of the diagrams that show using a 249 and 1.5 K ohm resistors on the white/green wires. I was just wondering if anyone knows any other way of making the wiring work. Any help is appreciated. Thanks. harry