I bought a Mazda3 about 9 months ago, and everything went fine up until about 3 months ago when the stock GPS went out on me (Blank screen) I was disappointed but didnt have the time or money to fix at that moment. Well about 2 weeks ago my car started to die overnight. I initially thought it was the alternator, but after checking it and finding it to be just fine, I started going through the easiest thing first, the fuses, I checked every single one with a multimeter and only found one to be giving off mA while the car was off. It was the Room fuse (Controlling the dome lights,GPS,Stereo,Trunk Light, maybe more?). After pulling that fuse and letting it sit overnight once again, I came to find it didnt drain the battery anymore. So, why I bring up the GPS is I feel it might be linked to it or something. Does anyone have any ideas as to what it could be and what I could do?

Oh, by the way, I replaced the battery 6 months ago and checked it as well, it doesnt seem to be the battery. Also, I dont know too much about cars so if you have an answer, try explaining it to me as simply as possible, Thanks!

 

You don't say what year your 3 is, but I know on our '10 3 s the dash is constantly humming. Can't hear it with the engine running, but there's something there running and drawing current. I would guess if you don't drive it regularly, it's going to drain the battery.

 

Sorry, it's a 2006 2.3. I don't hear a humming but the fact that I can't leave it for over 8~ hours to sleep without it going dead, is really frustrating. I'm wondering if a circuit has gone out on the fuse box...?

 

Have I got a goody for you to read: https://www.mazdaforum.com/forum/maz...s-27572/page2/ Post 17 is where I make progress.
Nothing you can do about the draw, just deal with it by insulating your battery and install a solar panel (it does not charge @ night). My draw was 120 milli amps (security system, dash light flashing).
Maybe your computer isn't shutting off, maybe there is a loose connection somewhere (GPS)---lights left on---door not closing properly or activating door light switch properly?.