If the '03 G is anything like the '03 350z, you can also lock the doors with the key. As far as your problem, I'm wondering if the battery in your keyfob is dying. It's probably 10 yrs old. I had a similar problem with my old '02 altima's key fob which is the pretty much the same. The alarm would arm itself but not always lock the doors. The problem seemed to go away when I replaced the fob's battery. Worth a try.ddemier7 wrote:when i arm my 2003 g35 coupe the horn beeps and the red factory security light comes on and alarm engages but the doors don't lock. I can open the door and the alarm goes off! Is this normal for a G? I'm a new owner of a G35. Any ideas?? I would like my doors to lock and there's no lock button on the door panel. This is a factory alarm settup .