New Home, existing system, no information on what current access code is
Powering down for several hours should reset the code to 1234.
To power down, find where it plugs into the wall. It'll be a big plug, about the size of your fist ( a three-inch, block style plug), black, white or beige in color, probably a little screw holding it in. It may be directly below the panel or could be in the room on the other side of the wall of the panel. Otherwise, it may be in a garage, basement or attic. It may be in a weird place, like behind a couch in the living room or on the ceiling in the garage. Good luck finding it!
Next, disconnect the back up battery. This can be tricky because it's really easy to break the little tab that holds the compartment shut. With the cover open, look at the top of the panel or the sides/corners. CAREFULLY push the tab, open the cover and disconnect the battery.
Leave it powered down for 24 hours and then plug in the battery first, then plug it into the wall. The code should (hopefully) be 1234 now. Read More At : Security Simon 3 Wireless Home Security System...