What kind of mods are we talking about here? If they are Tuning Mods, for example, their presence won't be announced in any way. They just work (or not) silently behind the scenes.
First thing to check, look for the file called DeviceConfig.log in this game folder into which you have placed this new Mods folder. Does its Modification Date/Time match the last time you launched your game (launch it if you aren't sure, the date/time stamp should change almost instantly). If it's not updating, then you have a different TS3 game folder someplace on your system that the game is reading from instead of this one.
If it's not that, have you deleted the five cache files in the top level of the game folder since adding all of this content? This needs to be done whenever the contents of Mods\Packages changes in any way.
And if that's not it, then perhaps we need to see some screenshots in Detail View of your game folder, Mods, and Mods\Packages to see if we can spot anything out of place. The structure should look just like the illustrations here, plus or minus some differences around the edges for different operating systems.
http://modthesims.info/wiki.php?tit...Setup_and_Files