Metra 70-7903 Receiver Wiring Harness

Connect a new car stereo in select 2001-07 Mazda vehicles

Item #: 120707903

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11 Reviews

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Metra 70-7903 wiring harness

This vehicle-specific wiring harness makes connections between your new car stereo and your car's electrical system.

First, attach the color-coded wires on your Crutchfield-supplied harness to the wires from your new stereo. If you're not using a soldering iron, we recommend that you purchase some wire connectors to secure the connections. Check out our handy article on three ways to connect the wiring harness here.

Now, once this harness is connected to your new stereo, you'll be able to plug right into your car's factory radio connector. This harness saves installation time since you won't have to cut factory wires individually, and it also enables you to re-install the factory radio if needed. A detailed instruction sheet comes with the harness. Warranty: 60 days.

Please read this important note: This harness may not contain provisions for every wire needed to complete your installation, and it will not accommodate special navigation, video, or factory steering wheel control connections. You will need a special adapter if you want your factory steering wheel audio controls to work with your new stereo.


  • 12V constant power
  • 12V switched power
  • chassis ground
  • power antenna turn-on
  • illumination
  • left front speaker +/-
  • right front speaker +/-
  • left rear speaker +/-
  • right rear speaker +/-

Note: Most vehicles will require additional installation parts — please identify your vehicle if you haven’t done so, then check here for a list of parts. You can also call an Advisor for more information.

Hands-on research

What's in the box?

Download owner's manual

  • Receiver wiring harness
  • Instructions

Product Research


Crutchfield Wiring Harness: Crutchfield wiring harnesses prevent you from having to cut your vehicle's factory radio plug when replacing your factory radio with an aftermarket head unit. Simply solder or crimp the Crutchfield wiring harness to your aftermarket head unit's harness (solder & crimps not included), plug the aftermarket head unit's plug into the rear chassis of the aftermarket head unit, and plug the Crutchfield wiring harness into your vehicle's factory radio plug.

Note: Installation tools, hardware, & accessories are not included & sold separately. Please see the Accessories tab for recommendations & availability.

Wiring Notes: If the Crutchfield wiring harness is not equipped with a ground wire, you will need to ground the aftermarket head unit's ground wire to the metal chassis of your vehicle. Some vehicle's may require you to bypass the vehicle's factory amplifier (in another location from factory radio) or hardwire certain connections. If your vehicle is equipped with factory steering wheel controls, an additional adapter is required & sold separately.

Wire Code Chart:

Wire Color Function
Red +12 Volt Accessory
Yellow +12 Volt Constant
Black Chassis Ground
Blue Power Antenna
Blue/white Amp Turn-On
Orange Illumination
White Left Front Speaker +
White/Black Left Front Speaker -
Gray Right Front Speaker +
Gray/Black Right Front Speaker -
Green Left Rear Speaker +
Green/Black Left Rear Speaker -
Violet Right Rear Speaker +
Violet/Black Right Rear Speaker -

The Crutchfield Car Selector: Please visit the Crutchfield Car Selector for your specific type of vehicle.

Our Product Research Team

At Crutchfield, you'll get detailed, accurate information that's hard to find elsewhere. That's because we have our own in-house Product Research team. They verify what’s in the box, check the owner's manual, and record dimensions, features and specs. We stay on top of new products and technologies to help people make informed choices.

Metra 70-7903 Receiver Wiring Harness Reviews

Average Customer Review:

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Very Good Harness

Written By Tj, Frederick MD on Friday, April 10, 2015

Crutchfield Customer Review (What's this?)

Excellent installation kit. Fit the factory harness perfectly

Great harness!

Written By Anonymous, Maryland on Wednesday, April 08, 2015

Crutchfield Customer Review (What's this?)

This Metra harness fit seamlessly mated my new Kenwood head unit to my 2007 Mazda 3. The harness included 2 connectors (powered antenna and remote amp) that were not being used. I was able to re-pin the unused wires to other places on the harness for connecting my new PAC-SWI-RC steering wheel control which prevented me from splicing into the factory wires which I was trying to avoid at all costs. This is a great harness, I would not hesitate to buy another when the need comes.

Pros: fits perfect, extra wires (in my case)

Cons: None

Needed but pins wrong

Written By Jmk, Redmond, WA on Sunday, February 22, 2015

Crutchfield Customer Review (What's this?)

Look, you need it. On my car, 2 of the pins that connected to the Axxess box and the antenna power were incorrect. After not getting this to work and a call to Crutchfield not helping, I noticed the wire mismatch when snapping the shells together. Took a few minutes to swap pins. It all worked fine. Cost me some head angling over two evenings. :-(

Pros: You need it

Cons: You need it to be correct

It works

Written By Doober, California on Tuesday, February 10, 2015

Crutchfield Customer Review (What's this?)

It works. Hooray.

Cheaped out

Written By ChrisC, Phoenix, AZ on Friday, February 06, 2015

Crutchfield Customer Review (What's this?)

Sadly, the manufacturer cheaped out with the harness. Only about half of the wires on the stock harness are filled. This isn't necessarily a bad thing, but they didn't include the pins and wires for the steering wheel radio controls!

So I had to move the amp connections over to the steering wheel radio pins (because I don't have an amp and had the non-bose radio). It was a pain pushing the pins out and then plugging them into the correct spots. Another $0.25 of wires and pins would have made this so much easier.

I have a 2008 Mazda Miata, non-Bose radio and steering wheel radio controls.

Pros: Don't have to cut into the stock harness. Plugs in perfectly. Colors on wires are industry standard.

Cons: Not all pin spots filled. Need to modify the wiring so it'll work with the steering wheel controls or cut into the car radio harness.


Written By Daniel A., Naperville, IL on Monday, January 19, 2015

My first time wiring a aftermarket radio and it was really simple u just matched the colors and u can put your stock radio back in whenever u want too.

Pros: Very easy and simple u don't really need the instructions.

Cons: the should make it a double way adapter.

Works as advertised

Written By Anonymous, Grandville, MI on Friday, January 16, 2015

Crutchfield Customer Review (What's this?)

Does the job well.

Pros: Works great, easy and quick install.

Cons: None

Metra 70-7903 Receiver Wiring Harness

Written By Edwin, California on Thursday, January 01, 2015

Crutchfield Customer Review (What's this?)

Simple wire harness

Pros: Easy set up and installion.

Cons: None

Needs help

Written By Ken, Sedona, AZ on Tuesday, November 18, 2014

Crutchfield Customer Review (What's this?)

The harness fits a Miata but 2 of the pins don't have or match the factory harness, hence you need to bypass the harness union...not good as they don't tell you this!

AMAZING and Simply

Written By Mr Bacon, Las Vegas, NV on Monday, November 03, 2014

Crutchfield Customer Review (What's this?)

Easy and best way to use the current wiring even with factory amp and sub woofer.

Pros: Easy and simply

Cons: NONE

Works perfectly

Written By Lee, Boston, MA on Tuesday, August 23, 2005

Crutchfield Customer Review (What's this?)

Took me 15 minutes to wire this harness up to my Kenwood stereo. Didn't really need the directions as the color codings were pretty much dead on. It even works with the dimmer in my car. Great product.

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