I have a 2006 Mazda 3 and the key fob just stopped working recently. After buying a new battery and reprogramming, it still didn't work. So I bought a new key fob and attempted reprogramming - still doesn't work. Is there a fuse associated with the keyless entry that I need to check? Any other ideas? When programming, the locks cycle but there is no response after clicking the remote twice.

 

the system for the FOB runs off the sunroof fuse I think, it's also the same fuse for the TPMS if I remember correctly - they used the same module for all RF communication, then again I think yours doesn't have TPMS on it as an option.
The module is above the interior dome light in case you want to go searching for loose wires or something.

 

do you have a second remote which worked before so you could completely rule out the first non-working one?

Does the visteon number on the new remote you purchased match the one you had?

Check all the fuses in both the PJB and engine fuse boxes. After that check out the KEU which as djs mentioned is by the map lights.