Hey Scotty, I've had a problem with opening the car with my keys "wirelessly" (Mazda 3 2005 1.6 diesel 100.000~miles). My key fob suddenly stopped working one day and I can´t figure out how to fix it myself. When I enter the key into the lock to open the door, all the doors open, and the button inside to close the locks also works fine. Both of the keys that I have can't open the car, I replaced the battery on the keys but it didn't fix it. I can only guess that the reciever for the signal doesn't work, or the center locking module doesn't work. I can´t seem to find anywhere online where the locations of these components are so I wanted also to ask where are they typically are, or if mazdas have it somewhere else than usual...
My key fob suddenly stopped working one day and I can´t figure out how to fix it myself.
Try reprogramming your key fob(s). Here are the steps: https://www.keylessentryremotefob.com/blog/2013/08/2005-mazda-3-key-fob-remote-programming.html
I tried that but it didn't do anything. The reason I don't think the key fob is the problem is because both of them stopped working to open the car, they still both flash a light when I click them
Next time, buy a car without any FOB. Traditional keys are the best ones and simple.