I purchased this Boss 560BRBG aftermarket stereo from Crutchfield for my 2012 Mazda 5. Installation and setup was pretty smooth, facilitated by Crutchfield’s support documentation which really surpassed my expectations. If you’re looking to tackle a project like this I recommend buying from them vs Amazon. But a few things were still tricky or non-obvious, so I’m going to share some of them here in case others struggle with some of the things I did.

To be honest, if I had noticed the handy wiring guide Crutchfield mentioned in my purchase email, I probably wouldn’t have had several of these difficulties, but I somehow missed it until just now.

First of all, you are going to have to solder some wires

If you’ve ever done a project like this, that fact is probably obvious, but I naively assumed that the Crux SWRMZ-64C Wiring Interface that came with my package would mean the whole thing was just plug n play. I got all the dashboard panels popped off and the old radio removed before I realized this, then ran out of time and had to put everything back together and wait until the next weekend when I had time to tackle the soldering.

Fortunately I had recently acquired a soldering gun and been getting some practice. You could maybe use crimp connectors or some other method instead of soldering, but the soldering was not that difficult, provides a better connection, and is more fun.

Removing the panels to get at the guts

This part was actually kind of interesting, turns out most of the panels on your car just pop off with the help of some trim panel tools and a philips head screwdriver. Again, something that is probably obvious to many folks.

One bit of advice I got from somewhere on the internet for this step was: after you’ve unscrewed the gear shift nob and popped off the gear shift trim panel, you can press down a little white lever with your finger or screwdriver to shift the car into neutral, which makes it easier to remove the climate control assembly. You could probably just do this at the outset. Obviously make sure your parking break is on.

Soldering the stereo wires to the wiring interface

Basically you can just follow the wiring guide from Crutchfield here, and match similarly-colored wires to each other. However

1. The manufacturer’s manual that comes with the wiring interface incorrectly identifies one of the wires as blue, when it is actually (in my case) brown. This is the Steering Wheel Control (SWC) Phone wire, which won’t be used for anything if you have the same year/model Mazda and this stereo. I soldered it to the brown wire on the stereo which turned out to be unnecessary, but not actively harmful.
2. The blue wire of the power antennae is similarly useless for this car, as the antennae doesn’t require power. You can just plug the antennae jack into the back of the radio, and top the blue wire off with electrical tape. Easy.
3. Because Steering Wheel Controls are simply incompatible with this stereo, flipping the dip switches on the interface module is unnecessary. Additionally, connecting the two wires that come out the other side of this module is also unnecessary, you can just toss those away, or keep them in your electronic junk box forever until you die because you will never use them for anything so just throw them away.
4. There will be an extra module just hanging out that connected to your old stereo, but has nowhere to go with the new one. I’m not sure what this is for, possibly SWC, but either way you can just ignore it and leave it hanging around. This little white guy here, no home for you any more buddy.

Mounting the stereo

I mostly ignored the mounting instructions that came with the stereo itself as they were confusing and seemingly incompatible with the Metra 99-7521B Dash Kit that was part of the package, and necessary to ensure you don’t have a gaping hole remaining in your dashboard.

I don’t have any good advice for this part, other than “just do what seems like it will work, ensuring that the unit is securely attached, without putting undue stress on the wires”.

Hearing this thing actually play a CD was probably the most satisfying feeling of accomplishment I’ve had in years.