I've followed everything in the manual about arming my security system, but I still havent found out how to arm it correctly, could someone please help thx

Don't have an 03, but a little more info on why you don't think its armed ? No confirming chirp ? No flashing parking lights on the X ? Horn not blasting ?
Solutions??
Alarm set to silent mode.
Bad battery in the remote ? Try the second remote.
If you are just testing it by arming it and opening it through an open window, it takes a minute or two before it fully arms before it will honk.
As a final test (on the remote end of things), leave the window open, lock it with your key, wait a minute, then open the door from the inside. (it should sound)
**note, if the remote isn't working, you'll have to dissarm by unlocking with the key, but I'm not sure if it will turn it off immediately, or when the alarm resets after sounding.

well, im pretty sure my battery isnt bad, and the light says its armed, but it wont sound. If it is silenced does anyone know how to un-silence it?

don't know if its the same way as the 00/01, but we held the lock and unlock button togther for like 3 seconds or something.

Yeah, that silences the horn when I lock the car, but it doesnt do anything to the alarm

What do you mean it won't sound?

The factory alarm is pretty limited - it only triggers in a few situations that are outlined in the owners manual (don't have it handy at the moment and too lazy to go get it).