custom module not showing up in modules list

I created a custom module to fix a problem in search that sees a search for "Y05-4" fail to produce any results - the problem apparently being it ignores the leading 0 when searching? However before I can even test the module I need to get it to show in the list of modules under Functionality and it won't show up despite a number of checks of syntax and so on - originally named search_zero_fix I renamed it fix_zero_search thinking thast might help but it doesn't. Its even got AI stumped!

Bet it is something simple though... can anyone point me in a way forward?