Chrysler offers a base security system for cars without power door locks. Security module #82203763 is $149.50 with wiring harness #82206015 at $31.05 when ordered on-line at
www.kollerdodgeparts.com. These factory parts are covered under your car's warranty. I would highly recommend you also order a factory shop manual. It comes in handy many times. I forgot to mention, #'s are for an '02 PT.