I bought a 2004 Titan with a after market security system. The problem I am having is I don't know how to arm or disarm the system, or how to lock and unlock the doors. I even pushed some combination of buttons and the truck started without the key being in it. The dealership doesn't know the brand of alarm and can't seem to contact the previous owner. Any ideas on how I can find out the alarm maker? The remote only has the words'TWO-WAY SECURITY' on the front. The front has a picture of a car with the time above it and a button with a lock on it and a button with a key on it. There are 3 buttons on the side showing a open car trunk, a 8 point star, and a circle with a 'C' in it. I'm open for any ideas.

you may just have a remote car starter, without an alarm. most are wired to the ignition wiring at the base of the steering colunm. if you look under the dash you may see where they tapped into the harness ( typically hacked into place ) and follow to a small black box, slightly larger than a wallet, typically wire tide in place, and get manufacture name off box. hope that helps.