Changing the factory radio headunit to a double DIN in a Mazda MX5 Miata NC (2006 – 2015)

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I’ve held back a fair while (7+ years?) with my stock headunit, but I think it’s now time as most of my trips are different enough to require GPS. So it would be nice to have it integrated into the dashboard somehow, and might go a reverse cam and a dash cam if it makes sense and can fit in the budget. And I don’t have time to go a super highly customised route like I did 20+ years ago before the days of carplay/android auto & extremely low cost and low power SOC’s – so this will be a more standard radio install albeit running Android.

My model is the Australian 2009/2010 NC2, PRHT, Automatic with Bose. The factory headunit looks like this in photos from my article on how to swap the evaporator in the Air Conditioner:

As you can see it comes with a state of the art 6 CD stacker that also reads MP3’s, to hold literally thousands of your favourite songs – playable within minutes.

Removing the entire fascia

I’ve already removed this once during the air conditioner repair & took photos as I knew this upgrade would happen sometime. However to get it removed is fairly straightforward, you can follow the first couple of steps in the AC article which is basically this:

Here’s how it looks from the back once removed, so we know what we need to find regarding wiring harnesses.

It’s already been done

Here’s a few videos from people who have gone through this process already, which we’re going to be getting some hints from regarding wiring trickery.

Now that I’ve found these videos, I’m getting suggested videos all for MX5 NC radio installs so there’s plenty of information out there to go astray!

There’s also a great writeup with a lot of tips (some I have discovered, others I wasn’t aware of) here: https://forum.miata.net/vb/showthread.php?t=769695

Shopping List

Now that we can see what’s there and how people have done it, we can figure out what bits we need to achieve this.

Fascia/Bezel/Frame

There are maybe 3 options for the Fascia I have discovered, someone bought three different ones and gave an overview here: https://forum.miata.net/vb/showthread.php?t=759111 , what I have discovered online is below.

My aim is to try to source the Scosche MA1550B for the slightly more OEM look especially around the aircon controls, and also it seems to have a slightly larger (taller?) opening to allow for the cheaper radios that I’m looking to get. I’m reading a lot of people are having to modify other options by filing or grinding to get radios to fit.

Radio

For the radio the goal is to keep the price on the low side ($200AUDish), not the absolute cheapest but not at the name-brand level (sony/kenwood/pioneer – $400AUDish). Here’s what I’ve found so far.

• Atoto / Revcarx
  • These seem to be about half the price of more popular brands while still doing all the typical google functions (like maps) and android auto which is what I’m after.
  • The models that keep getting mentioned are:
    • A6PF (2022, 2gb), A6PL (2024 refresh? 4gb? QLED), A6PP (2025? 2gb/4gb/IPS/QLED??) <– the A6 range seems to be the common one people go for.
    • A5L (2025, 2gb, absolute cheapest models)
    • A7 (Linux based, not android but does android auto, has odd gremlins?)
    • S8 (mid-range, costly, 4gb)
    • 10X (top range, expensive)
  • The differences being the design of the front (buttons or touch-buttons, exposed usb), the display technology (IPS vs QLED), Android version, & ram/cores.
  • Popular opinion is if you can afford it and it makes sense for the car, go for at least 4gb ram and QLED.
  • They seem to have packages with cameras.
  • Extreme sales on Aliexpress during big holidays.
• Eonon
  • Only just eyeballing these as another budget option. Don’t seem as prominent as Atoto
  • They get a decent review, and have more recent android versions?

Currently leaning towards the Atoto A6PL (A6G2B7PL), or the S8 if it’s cheap enough.

Wiring looms & other

Note: The smaller white plug that goes in to the back of the stock MX5 radio seems to be ignored by everyone – mine has one and the only thing I’m aware of is the AUX port down in the tray area, so once I have the radio out again I’ll trace this to confirm what it does. I’m going to be very annoyed if I had bluetooth available for 7 years! Ok I have found photos I took while it was apart and a wiring diagram. The smaller plug seems to be more so the stock radio can react to the cars speed, lights, all of that – like a CANBUS. And also the AUX. So this is why people are ignoring it. I might see if I can wire up the AUX socket to the new radio anyway since I’ll be in there.

So this is what I have come up with from the videos.

For all radios:

If you’re going for a big name brand (sony/pioneer/kenwood/jvc/etc.) radio:

• Parking break bypass cable (this is radio-brand specific) – apparently only required for name brand radios, for Atoto we can ground or just leave disconnected the parking break wire as I’ve read there’s a software setting to override it anyway.
• Metra ASWC (for steering wheel control translation – the Atoto contains an app to do this without the hardware, I’m unsure of others)
• You may need 2xline-out converters if you have an amp already (BOSE for NC2) and your radio doesn’t have RCA outputs (These come with SOME Atoto’s, others have the RCA outs already)

And a microsd card for the dashcam.

And a short radio antenna extension lead as these radios are shorter than the stock so it’s tight.

All the parts

The parts are slowly arriving, so this will continue to be updated until they’re all here.

That’s everything required as far as I can tell, aside from any little items I can source locally such as cable ties, bolts, and black tape. Lezdoit!

Fitting the radio in the faceplate/bezel/fascia

I ordered the Scosche MA1550B double DIN fascia but what arrived was the Metra 99-7519B that most people are using in the videos. While it’s the correct equivalent it has different styling which I was trying to go as close to OEM as I could. I have been refunded and this allows the project to go ahead, but if the looks aren’t quite right I might still try and source a Schosche. Let’s see!

Fitting the radio in the Metra (WITHOUT the double din side rails) shows that indeed the opening is slightly too small, so the Atoto’s plastic faceplate rests on the lip surrounding the opening. Once the side rails are put in it makes the radio sit on top of those rails which results in it poking out a little too far. So the aim is to modify the rails only and I think it’ll be good enough.

So what the other person suggested is a good start, making some little slots for the screws to slide in to which I did on both sides but the radio still sat a little too far out as now with the screws slotting in, the radio’s faceplate is now sitting on top of the DIN rails. So I had to cut a channel all along the top of the rails (not too deep) which then allowed it to sit as flush and securely as possible and just barely align with the screw holes behind. With that the radio sat flush against the inside lip again.

The included Atoto surrounds don’t fit in the metra, so the Metra-included surround needed to be modified by having its long clips removed. It’s also not as deep as the Atoto front so it’s now attached using strong (and thick) adhesive tape to both the front and sides of the radio which holds it firmly in place and raises it to roughly the correct depth.

Hooking it all up

I followed a combination lf all diagrams.

Here’s the result of all of that wiring:

There’s a lot of mention about borrowing two pins from one harness and adding them to the other (1P, 1N) for Steering Wheel Controls (SWC). Mine was actually missing a third (1J) for AMP control, which I have added in also. There were two different opinions about this – wire the Antenna up to both 1J and 1H, or wire them directly and adjust an amplifier setting within the Atoto itself. I’m attempting the second approach.

Also from what I could find online with 1P and 1N, the trick is to combine Steering Wheel Key# (+) to both 1N and 1W (these are the joined red, black, and brown wires in the centre of my picture, effectively ground), and Steering Wheel Key (+) to 1P. Update: This is confirmed to work perfectly.

The only other multiple join is the reverse camera, needing to splice in to the ACC wire. On the other end of the reverse camera there was a lot of work as the wiring isn’t long enough.

Routing the wires

The front wiring was fairly straight forward – most of it is hidden under the front cowl which is easy to get back to the radio hole.

The Dashcam is fairly straight forward to push under the top plastic, and I took the side plastic off also (you have to remove the bracket the roof slots in to first). Then it all channels through the glovebox to get to the radio hole. Very easy. The reverse camera is an entirely different story.

The initial plan was to run the cable through the middle channel, but I just couldn’t get anything to poke through to the boot from there (maybe due to PRHT?). So I reluctantly ran the cable along the passenger door to come out alongside a wiring loom near the fuel pipe.

Update: I have completed this and the camera is mounted and functioning perfectly – but I HIGHLY recommend just doing the typical number plate/rego plate camera (with the wide mounting bracket). That way all the cables are in place at the correct length and you’ll save yourself a day of extending every wire, with practically the same result.

Ok I can see the rust too

When removing the carpet to take the plastic panels off in the boot, I noticed it was damp at the rear which the car was in a storm the previous day so I wasn’t overly surprised. Also when I took the panels off I was faced with rust (surface, nothing scary) which when I looked at photos from when I did the sound deadening 5+ years ago there was no rust there. So something is leaking. The common issues are the rear lights needing new gaskets, and the top brake light (sometimes called the 3rd brake light) needing sealing. So may as well check and/or fix those at the same time since we have it apart. I did notice I was able to push the right hand brake light a little when washing the car.

I have removed the old seal, and fashioned new gaskets out of neoprene rubber that I have left over from the Airconditioner fix that I did a few months ago. It seems to fit snugly so I’ll see how it goes in the rain! I have a feeling the right light was only leaking because it was very slightly loose.

Also in my research the 3rd brake light on PRHT models don’t leak in to the boot – they are in the folding roof area which contains many drain channels. There was a forum thread somewhere that was questioning what drains the 2006-2015 PRHT model had so I have taken photos of the area incase someone stumbles upon this so it can help.

A few handy hints

• Offline google maps requires you to sign in, and google maps don’t load or work at all unless you have a locked GPS signal
• OBD2 on this car is incredibly useful, as you get fuel levels and remaining range in the tank amongst other nifty things.
• I haven’t used android auto yet, but apparently for a more reliable android auto experience (if required), get “Head Unit Reloaded (HUR)” from the play store.
• If you wired up the lights wire, the screen apparently has two brightness settings – one while the lights are on, one while off. There’s a setting somewhere to auto blank the screen after inactivity, and this is apparently a good screen blanking app if you need it: https://play.google.com/store/apps/details?id=in.binarybox.blackscreen&hl=en_US
  • Update: The Atoto A6PL contains an auto blanking setting, and also 3 levels of brightness in the quick status menu. I would recommend the auto blanking if driving at night.
• There’s been a few mentions online about these units draining peoples batteries depending on different driving habits. They apparently have a standby time of 3 or so days, so if you just move your car out of the garage every 3 days it keeps it semi-awake and the battery doesn’t charge enough. If you drive every day it’s not a problem as it’ll charge back up. So an override power switch (on yellow?) might be a good idea.
  • Update: There is a secret settings menu that allows you to set it to shutdown every time instead of standby. In settings, tap “System” 4 times, put in 3368 as the code, then set “System is turned off Sleep/Shutdown” to disabled or no sleep.
  • Update2: Here’s how Atoto explains it: https://www.atotodirect.com/en-au/blogs/guides/atoto-car-stereo-bgsleep-with-instant-wake-backup-priority
  • Update3: I had the shutdown option set as that suits my driving habits more, but what then happens is if you are sitting with the car on ACC fiddling with the radio, and start the car, the whole unit resets. So I have changed it back to the default sleep option to see if my battery survives!
• The Atoto A6PF (and hopefully PL) has dual bluetooth radios, so you can pair a bluetooth OBDII scanner in BUT this takes the 2nd bluetooth channel so you can no-longer use that for phone data.
• This unit can do data over bluetooth with your phone – if it’s not working then check your phone has bluetooth tethering enabled within the network and internet settings (NOT in the bluetooth settings!), and your phone also needs to be connected to both Bluetooth 1 (for calls) and Bluetooth 2 (for data)
  • Update: Apparently bluetooth phone data is unreliable, so others are using macro apps to enable & disable their phone’s hotspot when it’s connected to bluetooth. https://xdaforums.com/t/atoto-s8-general-discussion.4114493/post-85815077 . This would also allow the OBDII scanner to continue to be connected.
  • Update2: I have set this method on mine resulting in bluetooth phone calls, OBD2, and wifi hotspot data all going at the same time.
• When setting Steering wheel controls, set the < and > to |<< and >>|, that way they will pass through to android auto/apple carplay also.
• There doesn’t seem to be a dedicated Night Mode or Dark Mode in this unit, you can only change individual apps and brightness, and use the auto screen blanking setting.

What’s next?

Changing the interior lights to leds so I don’t worry if they are left on, and maybe routing a dedicated 12v ACC line and socket to the boot for charging things on the go. Will see.