I am running wiring for interior lights on my 09 mazda 3. Can anyone tell me the best way to tap into a constant power supply ? I usually run the wires right to the battery but I can't find any extra holes to do so. Or does anyone know where or how I can get through the fire wall? thanks

 

Try the fuse panel on the passenger side underneath the glove box. You'll definitely be able to find yourself a constant supply of power in there.

 

You can also tap the back of the cigarette lighter for a 12v switched on the ignition, or the lit ring around the lighter for 12v switched with the lights..... it all depends on when you want your lights on.