Help with stereo upgrade

[bassmannate]

There's really only a couple wires that could be causing that. Either the constant power that retains things like radio presets and provides the bulk of the power for the radio or the ignition wire that tells the radio to power on. Looks like the constant power is blue at the tuner and ignition is gray. These are a little goofy since they're basically a Mazda 3. Tuner should be above the passenger's kick panel. Either you have a broken wire or a blown fuse. I don't have access to full wire diagrams here but this should help you if you haven't figured it out by now.