I've seen posts stating that the DLR hardware is installed but not all Altimas have them activated. This makes sense economically and other auto manufacturers do the same thing. I have various rumors like that only the 3.5 engine option has them, but not all do. I believe either a jumper cable or software patch probably activates them given the right options packages selected, so those of us with base models go without. There has to be a simple way to activate them, and I would simply ask a dealer service tech what the deal is. I have a very base S model -- there isn't even an "S" emblem. My DLRs are out too, so if anyone finds the solution let us all know.