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PAC C2R-AUDI Wiring Interface

Connect a new car stereo and retain the factory Bose® or Symphony audio system in select 2004-up Audi vehicles

Item #: 127C2RAUDI

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22 Reviews | 1 question - 1 answer

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PAC's C2R-AUDI radio replacement interface lets you replace the factory radio in select 2005-up Audi vehicles, while retaining use of your factory-installed Bose® or Symphony amplifier. Warranty: 1 year.

Please enter your vehicle information or call an Advisor at 1-888-955-6000 to find out if this model is compatible with your vehicle.

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

PAC C2R-AUDI Wiring Interface Reviews

Average Customer Review:

22 Reviews

Instruction read like legal documents.

Written by: Anonymous from Connecticut on December 25, 2015

2005 Audi A4
Crutchfield Customer Review (What's this?)

Bought this product with the rest of the installation kit. The instructions were satisfactory on how to connect everything but had a tough time getting the rear speakers working. But the info was found on the Internet since it was not covered in the directions.

Pros: Everything included.

Cons: Wires were not pre stripped made the installation take a bit longer. Instructions were hard to decipher

Seems like stock quality was sacrificed

Written by: wicklunds from Washington on November 27, 2015

2008 Audi A3
Crutchfield Customer Review (What's this?)

It's difficult to make comparisons after the stock system has been replaced. Let me begin by saying I am satisfied with the new styling of the upgrade from the Audi concert system. What I am feeling a bit less enthusiastic about is the sound quality when the volume is lower. I realized there were going to be trade-offs when making the change but it seems a shame to dole out more money and have to make such compromises. I don't know about the wiring interface quality. What I can say is that the steering wheel controls are strangely sluggish and seem to work intermittently. They are not as fine-tuned and crisp as the stock controls were. Make sure you understand that when changing from Audi stock sound systems.

Pros: Updated styling and touch-screen interface. More customization options. Better depth of base with the powered subwoofer. Enjoyment of a more modern-looking stereo face.

Cons: Sound quality sacrificed at least on a small scale from what little I know of wiring and electrical/sound system installation and customization. Steering wheel controls sluggish and awkward. It seems to sound like less of the surround-quality stock system that the Audi Concert system provided.

Solid product

Written by: CC from Ohio on November 1, 2015

2006 Audi A4
Crutchfield Customer Review (What's this?)

This product made it easy to install the aftermarket radio.

Pros: Made the conversion on my old Audi A4 easy. Once I figured it out it was straight forward.

Cons: Couple of recommendations. The directions need beefing up. The package includes two conversion kits so the instructions should make it more clear which on should be used based on the car. Secondly, a nice added touch would have been to pre-cut the wires to save time cutting the wires prior to installing the radio. Minor complaints but worth considering.

Easy to install but the instructions could use work

Written by: K2 from New Jersey on October 6, 2015

2008 Audi A4
Crutchfield Customer Review (What's this?)

It works well even though it doesn't really help with the significant low volume issue for rear Audi speakers. The instructions were quite confusing making the install seem more difficult than it actually was. The easy lock interface was extremely convenient. Worked very well in conjunction with the steering wheel adapter though it would have been nice if it was all just one unit.

Pros: Easy to connect to the stock connector

Cons: Instructions were unclear


Written by: MattS from North Carolina on July 7, 2015

2007 Audi A4
Crutchfield Customer Review (What's this?)

Works perfectly

Pros: Easy interface works like factory


PAC C2R-AUDI interface

Written by: Maddog from Michigan on June 28, 2015

2007 Audi A4
Crutchfield Customer Review (What's this?)

Was very easy to install and use, instructions were a little intimidating but in the end everything worked.



PAC C2R-AUDI Wiring Interface

Written by: C. K. Eskew from North Carolina on May 30, 2015

2007 Audi A4
Crutchfield Customer Review (What's this?)

The harness was pretty easy to install. The receiver works well with the car.

Pros: Almost. Flawless integration with the car.

Cons: Wish it kept the functions of the OEM system without having to buy another harness adapter to use multi function steering wheel.

PAC C2R-AUDI Wiring Interface

Written by: OldWolverine from Florida on April 19, 2015

2005 Audi A4
Crutchfield Customer Review (What's this?)

The documentation on this sucks. Fortunately the Alpine has few wires that aren't obvious.

Pros: You get all the connections you need so you don't have to cut up your factory harness once you figure out how to connect it.

Cons: Lack of a nice line drawing showing how the Radio and all its adapters connect to the Audi. Nothing shows where the Accessory wire goes on the Radio.

Crutchfield response on April 20, 2015 We forwarded this review to our Technical Support team for follow-up. Lifetime tech support comes with every Crutchfield purchase.

as advertised.

Written by: randel from Cookeville tn on December 5, 2014

2006 Audi A4
Crutchfield Customer Review (What's this?)

Worked like it said it would. Made the job a task I could accomplish.




Written by: vinny110 from albany,ny on August 20, 2014

2005 Audi A4
Crutchfield Customer Review (What's this?)

good product

Pros: n/a

Cons: n/a

PAC C2R-AUDI Wiring Interface

Written by: Anonymous from Aviano Air Base, Italy on February 23, 2014

2008 Audi A4
Crutchfield Customer Review (What's this?)

This interface was pretty easy to instal into my 08 Audi. The issue was splicing the new head unit wiring harness into this new wiring harness. My wife and I had to find a local audio store to purchase a slice kit to complete the install. Overall it did make the install a lot easier.



PAC C2R-AUDI Factory Integration Adapter

Written by: Anonymous from CA on January 6, 2014

2005 Audi S4
Crutchfield Customer Review (What's this?)

Extremely poor documentation. 3 weeks and I still haven't worked up energy to try and figure out the wiring scheme to marry up to the headunit that I purchased at the same time. Guess we will have to see if it works once I've given it a shot.




Written by: Karl from Denver, CO on December 23, 2013

This rating would be higher by one if I could just get the steering wheel controls to work! All-in-all, this is a whole lot of hardware to try and shoehorn behind my deck and that would be a lot more acceptable if the steering wheel controls would work. So far, after numerous attempts to program the PAC SWI-RC module which was shipped with this harness, I have had no joy. I even consulted with an Tech from PAC and he just told me to try what I already have. The C2R-AUDI module has a red (red=danger/fail...right) LED inside it, but I am told this is normal. I wish that Crutchfield supplied better adapters, because I would not have had to program anything and my job would be done. I have already had to purchase radio and GPS adapters because the ones supplied were incorrect for my car and am now debating scrapping this product in favor of something less complex and more compact which actually works in my car! I ended up having to create my own connection diagram from three diagrams.

Pros: Supposedly communicates with the car bus system and enables steering wheel controls.

Cons: Exceptionally bulky, confusing interface to aftermarket deck and still have not been able to get the steering wheel controls to work! Took extensive research to find how to connect this up correctly.


Written by: Dave K. from MI on September 3, 2013

2007 Audi A4
Crutchfield Customer Review (What's this?)

Fantastic adapter system with a clear wiring diagram, I couldn't imagine doing the install without it. Allowed you to leave the factory wiring harness completely in tack.

Pros: Clear and easy.


05 Audi A4

Written by: Fireproof from Denver, Pa on July 21, 2013

Crutchfield Customer Review (What's this?)

Disappointed at first, Adapter was suppopse to plug right in. Yeah right, only one of the plugs worked for the front speakers. Called Crutchfield Tech was alittle annoyed when I called. So I went on line and typed in 04 Audi radio install and sure enough there were install tips for the same kind of radio down to the pictures. That was the biggest help. This product said NOTHING about the factory amp or sub woofer. Called Crutchfield later and now I'm Happy, Happy, Happy

Pros: None

Cons: Still had to cut harness to make it work

07 Audi radio adapter

Written by: SamW from Sugar Land, TX on July 3, 2013

2007 Audi A4
Crutchfield Customer Review (What's this?)

Everything seems to be working pretty well and it was easy to setup. I did have to call tech help for a few wires that I could not figure out what to do with. So other than having a little bit better instructions, this is a great kit for being included with purchase free.

Pros: Free with purchase, easy to setup and wire, great tech help

Cons: Need more detailed instructions

PAC C2R-AUDI Wiring Interface

Written by: Anonymous from Kenosha, WI on April 27, 2013

Crutchfield Customer Review (What's this?)

Only complaint is the installation instructions were missing some valuable information about the red wire and where to connect it.

Pros: Easy to hook up

Cons: Needs more complete instructions

needs wiring diagram

Written by: chris13 from Lake Charles, LA on April 25, 2013

2007 Audi A4
Crutchfield Customer Review (What's this?)

this is the third or fourth stereo i have installed and this one sent me for proffesional assistance. there is no good wiring diagram with this adapter (or with the PAC SWI-RC for a car with steering wheel controls). so yes it works, but figuring out what needs to get connected to what is impossible. I finally gave in and went to a local audio store and even they got one of the connections wrong so every time i turned on the headlights it thought it was in reverse and would only look for a camera!

I have relied on crutchfield in the past for the availability of good instructions and diagrams but this time i was let down

Pros: does what it says

Cons: no wiring diagram makes install very difficult

Not too bad

Written by: Ben from Northeast PA on January 21, 2013

This kit is pretty easy to wire, If you have some electronic knowledge. I took the single page that came with this kit and set it next to the diagram for the specific receiver and it enabled me to answer any questions I had on what all I should connect. MUCH easier and less painful than my 2002 Audi TT. Recommend getting the Steering Wheel Control if you are used to using them. It bothered me on my first drive not to have them functioning.

Pros: Easy hookup and can-bus interface.

Cons: very little explaination in instructions for beginners.

Works well, Needs a documentation refresh

Written by: Luke L. from Richmond, VA on March 28, 2012

2005 Audi A4
Crutchfield Customer Review (What's this?)

This product allows easy integration with the complicated wiring of the stock Audi head unit, and handles emulation of all the CAN bus signals. The only thing that was not mentioned in the documentation is for users with the Bose package you need to hook the Blue/White wire from the red connector to the correct wire to turn the amp on. On my Kenwood head unit, this wire was labeled Power control/ Antenna control and was also blue and white. Also, if you get the FM antenna connector adapter, don't forget to wire up the blue wire to +12V while you're preparing the harness. I had to re-splice that wire when I realized the antenna needs power.

Pros: Easy install, all factory functions work properly

Cons: Documentation needs to be fixed

PAC C2R-AUDI Wiring Interface

Written by: Anonymous from Orlando, FL on January 24, 2012

Crutchfield Customer Review (What's this?)

Make sure before buying any products from this maker that you know which pieces come in the package. I bought the product under the impression from the description and parts that I would have everything I needed in order to keep the functionality of steering wheel controls. Little did I know that there is another $100 dollar piece you have to buy to enable these functions when the description talks aboit needing this package to keep steering wheel controls. Was pretty disappointed when I wored everything together and realized that, wait, where is the swc box. Oh, I have to order it too. If you have swc, call a Crutchfield rep or another professional and find out. Or your budget for your project will get much bigger.



PAC C2R-AUDI Wiring Interface

Written by: ScottC from Fort Worth, TX on March 26, 2011

2005 Audi A4
Crutchfield Customer Review (What's this?)

The product works flawlessly, but the hook up process could be a lot easier.
The instructions were barely adequate, without a good dose of common sense on the installer's part, it could be a huge problem.
The RCA hookups for the rear speakers had me puzzled. Why are they RCAs? Luckily, after getting the matching RCA and connecting them to the new stereo's harness, everything else went fine.



Hands-on research

What's in the box?

Download owner's manual

  • Audi radio replacement interface (with CAN-bus)
  • 2 Vehicle harnesses
  • Instructions

Product Research


Overview: The PAC Audio Replacement Radio Interface (C2R-AUDI) allows the replacement of an original Audi factory radio with an upgraded aftermarket radio in select 2005-2010 Audi vehicles. The C2R-AUDI has been engineered to interface seamlessly with Audi's CAN-bus data system and retain important features that play through the factory radio and provide necessary power wire connections for the aftermarket radio that are otherwise not available. The PAC C2R-AUDI will provide navigation trigger wires and data driven accessory output for replacing the factory radio in select Audi vehicles. It also retains the factory installed BOSE or Symphony audio system. Use with a PAC steering wheel interface module (541SWIRC, sold separately) to retain function of all factory controls.

Compatibility Chart:

Audio Vehicle Model Year
2005 2006 2007 2008 2009 2010
A3 N N N Y Y Y
A4 Y Y Y Y N N
S4 Y Y Y Y N N

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.

Customer Q&A

1 question already asked

For details on fit or installation please contact an Advisor by phone (1-800-324-9695) or online chat. They will be able to pull up your vehicle and give you the details on if this will fit and what you will need for an installation in your vehicle. [ Krissy  Mar 13, 2015 ]  Staff

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