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4 Posts
Discussion Starter · #1 ·
Overall the process wasn't too bad.
This was my first time installing a car stereo but from what I've seen pioneers/alpines should be similar.
I tried adding links to the guides that helped me but I'm under the post limit.

Parts you need
  • Double din radio
  • Metra 70-7903 Harness
  • iDatalink RR
  • Metra 40-HD10
  • Dash kit (I got the SCOSCHE MA1543B 2010-13)

Tools you need
  • Wire strippers
  • Electrical tape

First of all take out the radio and Metra 70-7903. The Metra wiring diagram can be found on the crutchfield website on the details tab. If you're just replacing the HU like I am, every wire should be used except for the blue/white one in the end. Start with attaching the white/gray/green/violet wires to your replacement radio harness. The wiring diagram for your radio should be in the instructions. Attach the orange for illumination.

Next take out the Metra 40-HD10 and attach the blue wire to the blue wire on your new radio and the blue wire on the 70-7903. All three blue wires should come together. Continue to attach the Metra 40-HD10 plug to the radio.

Now take out the iDatalink RR. Don't forget to flash it first using Internet Explorer The wiring diagram should be easy to find on their website. Only 6 of the wires are used from the bigger harness. Brown/red means more brown less red, this is important since there are red/brown wires. Two of the wires, purple/red and black/white attach to the Metra 70-7903. The gray/red wire attaches with the radio red wire and 70-7903 red wire. Again you will have 3 wires together. Attach the other connector with black/yellow/red wires and 3way the yellow wire to the radio and the Metra. Now finally do the ground (black) wire the same way, however with my radio I also grounded my (PARK SW) wire in order to use the radio while driving. Attach the black cable from the RR to the radio.

Assemble the dash kit and attach it to the radio. finish wiring anything you need for the radio (gps/microphone/ usb/etc).

Now you're ready to replace that stock radio. Follow the multiple guides on youtube or this forum to remove it. Remember to unhook the negative end on the battery before doing anything.
Once it's removed you'll see 3 plugs. You'll only be using 2 of them. One for the Metra 70-7903 and one for the Metra 40-HD10. I have no clue what the 3rd one does. I'm guessing it's for stock radio screen that becomes useless after this install (other than saying hello to u when you turn the car on)

At this point I would turn the car on and make sure that the speakers and radio are working. Remember that you still have 3 wires to install if you want to retain steering wheel controls and OBD2 gauges (this part sucked in the freezing cold garage)

I followed a guide from mazda3forums(dot)com/ 10008649-post174(dot)html to get to the wire needed for steering wheel controls. It's under the passenger glove box that you have to remove. It's a pink wire in a connector, connected to a module that says Bluetooth on it. I routed the pink/red wire from the maestro through the car to the spot where I needed it. It wasn't too hard, I'm sure anyone could do it with a flashlight, looking where the light comes through. I would recommend getting some splice connectors because that's what I did and it worked. You can unplug the connector since you don't need factory bluetooth. Then I put everything back together.

Now for the obd2, I went through the fuse box. I followed a guide on mazdaspeedforums(dot)org/forum/f429/how-hardwire-second-obd-ii-connector-into-135081/
I was able to get to the obd2, but the wires from the RR weren't long enough so I had to get extra wire to run from the obd2 area to where I had the radio. I spliced the extra wire into the obd2 wires according to the RR wiring diagram, and then connected those to that appropriate Maestro wires. From there all I did was route the gps next to the blue screen, and the mic in front of me, behind the steering wheel. I routed the USB on the left side where I routed the mic.

Once you put everything back together it should work perfect. Please let me know if you have questions/ I missed something in my guide.
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