Metra 70-1787 Receiver Wiring Harness

For select 1994-07 Audi and Porsche vehicles

Item #: 120701787

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56 Reviews

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Installation Note: This harness uses your factory amplifier; your new stereo must have two pairs of preamp outputs to connect this 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 don't know how to use a soldering iron, we recommend that you purchase some wire connectors that you'll use to attach the Crutchfield-supplied harness to your factory harness.

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 makes installing your new stereo easier, and allows you to put the factory radio back when you sell your vehicle or return it at the end of the lease. 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.

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.

Metra 70-1787 Receiver Wiring Harness Reviews

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56 reviews
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Nice solution, easy to use

Written By SGL, California on Thursday, November 26, 2015

Crutchfield Customer Review (What's this?)

While not actually plig and play the adapter fits the Porsche 911 Cab plug firmly. The plug is large but there is plenty of room for it. The low level RCA harness to the stock amp worked very well and was a hure help

Pros: Firm stron connection, low level RCA jacks.

Cons: Plug are large ( I assume to accommodate different models ) but fit well and simplify installation

Works 100% in my 2001 Allroad

Written By BigChiefS4, Minnesota on Wednesday, September 23, 2015

Crutchfield Customer Review (What's this?)

This kit works 100% perfect in my 2001 Allroad when installing a 6 year old Premier car stereo. If you're using the RCA jacks for speaker connections (which you will if you have the Bose system), you will need TWO PAC-SN1's to get rid of popping noises when starting and turning off the car.

Very easy install

Written By Stefan S, Philadelphia, PA on Wednesday, May 27, 2015

Crutchfield Customer Review (What's this?)

Can't mess this one up, plug and play.


Written By J, Ca on Monday, May 11, 2015

Crutchfield Customer Review (What's this?)

Great harness

Cons: No rear speaker hooks ups for my Audi from the stock harness


Written By Anonymous, North Carolina on Tuesday, February 24, 2015

Crutchfield Customer Review (What's this?)

The harness works well but the instruction need clarification when it comes to the power antenna connections and possibly the front speaker connections when it comes to using an amp.

Pros: Good hardware

Cons: weak instructions


Written By David, Bristol Va on Monday, February 23, 2015

Crutchfield Customer Review (What's this?)

Allowed the use of my factory Bose speakers with easy wiring.

Pros: Simple and effective

Cons: somewhat bulky for a tight dash installation

Metra 70 -1787: Harnessing Sound

Written By TomL, Blacksburg, VA on Wednesday, January 28, 2015

Crutchfield Customer Review (What's this?)

The product, upon receiving it, looks like a cross between an IED and Legos. However, it perfectly fits the stereo for my audi a3 at the perfect price (some goon at an audio supplier told me rivaling harnesses could run as much as $200! Preposterous). This product helped me replace the piece of German garbage that is the Audi Concert radio. The harness let me almost plug-and-play in terms of the stereo, and finally I can have use of an aux cord. Now I can roll down the block blasting Tibetian throat singing tunes or my cousin's grindcore band! Thanks! In any sense, I would recommend this product to other 2006 Audi A3 owners who plan on doing a DIY stereo replacement for a non-premium stereo.

Pros: Easy to use, clear instructions,

Cons: Didn't come with custom instructions as ordered, pre-stripped wires, some labeling for wires was unclear.

Metra 70-1787 Receiver Wiring Harness

Written By Mac, Arizona on Thursday, January 15, 2015

Crutchfield Customer Review (What's this?)

This was the suggested wiring harness suggested by Crutchfield for the ordered stereo and my vehicle information. It worked great and made installation simple and effective without destroying my vehicle.

Pros: Provided a perfect match for installing the stereo I picked with my vehicle.

Porsche wiring adapter

Written By Dean, Virginia on Wednesday, December 10, 2014

Crutchfield Customer Review (What's this?)

Clear instructions for an easy installation.

Metra 70-1787 Receiver Wiring Harness

Written By Anonymous, Ledyard, CT on Thursday, October 16, 2014

Crutchfield Customer Review (What's this?)

Worked so well

Pros: Everything fit well and the directions were very clear.

Cons: Had to change one wire to fit my car


Written By JC, COLBY KS on Thursday, October 02, 2014

Crutchfield Customer Review (What's this?)


Works Like it Should

Written By Dave, Lynchburg, va on Monday, September 29, 2014

Crutchfield Customer Review (What's this?)

Easy to use with the provided directions. Quick and easy connections.

Pros: Fast and easy connections.

Cons: None

wiring harness

Written By Anonymous, Hailey ID on Thursday, September 04, 2014

Crutchfield Customer Review (What's this?)

Product simplified my install took minuets to do

Pros: Clean professional look

Audi conversion with Alpine Radio

Written By Jerry, Wyckoff NJ on Saturday, August 23, 2014

Crutchfield Customer Review (What's this?)

Excellent fit and easy to install, anyone with a little intelligence can do this install...

Pros: All Pros everything is easy and everything fits very well

Cons: None

Great product

Written By D23, Yankton, SD on Thursday, August 14, 2014

Crutchfield Customer Review (What's this?)

Great product, shipped promptly, and made the installation of my aftermarket CD/DVD/Navigation reciever into my 02 Audi A4 a breeze!

Pros: Ease of connections , and easy to understand diagrams

Cons: No, had to run power to fuse box. connection on the harness for constant power

Doesn't work

Written By Andrew, California on Wednesday, July 09, 2014

Crutchfield Customer Review (What's this?)

Terrible. Doesn't work, doesn't give you half the audio you need for a functioning system in Audi brand vehicles. The problem is the factory amp needs more voltage than a standard aftermarket radio and this harness would lead you to believe. I bought a smart harness from Enfig and it works great, you'll need it.

Pros: cheap

Cons: everything but the price.

perfect fit

Written By Stephen, Atlanta, Ga on Monday, March 17, 2014

Crutchfield Customer Review (What's this?)

it was a perfect fit, very easy to install

A big help

Written By DieHardNYYFan, Charleston, SC on Wednesday, March 05, 2014

Crutchfield Customer Review (What's this?)

This little beauty was a huge help in simplifying the installation of the radio in my son's 2004 Audi A4. I definitely recommend also purchasing the crimping connectors as that would have made the setup even easier. I originally planned to solder the connections together with the leads from the radio but my iron crapped out on me. I went with plan B - small wire nuts and electrical tape - which worked just fine but made the final assembly a little bulky. This is a catch-all connector for the Audi/VW cars of the era so there are some wires that are not used. I cut them back and taped them to avoid a possible short circuit. Using this connector made it painfully simple to connect the radio to the car's wiring harness.

Free and Simple

Written By some guy, Charleston, SC on Tuesday, February 04, 2014

Crutchfield Customer Review (What's this?)

Crutchfield is awesome for throwing in the whole installation kit for free with my JVC unit. This wire harness worked perfect and they gave me everything I needed for my 02 Audi A4.

Pros: Simple to install and works.

Nice and free

Written By jozaan, ny, ny on Monday, December 09, 2013

Crutchfield Customer Review (What's this?)

Worked with no problems

Pros: It worked

Cons: None

2001 Audi TT receiver wiring harness

Written By Mike, MA on Monday, October 28, 2013

Crutchfield Customer Review (What's this?)

I bought this harness and installed it along with an alpine head unit for a friend and their audi TT. This car had a rats nest behind the original Bose system but this harness made the install super easy.

Pros: Affordable price Fast shipping Came with instructions (free)

Cons: N/A

It's Crutchfield or nothing!

Written By DJL, Scranton, PA on Friday, September 06, 2013

Crutchfield Customer Review (What's this?)

I have installed countless car stereo's, my Audi A4 that this went in to was the biggest PITA out of every radio I've installed! I had originally made the mistake of buying the first wiring harness from another store, that harness wasn't wired right and was shorting out. So I ordered this one from Crutchfield with 2day shipping and couldn't be happier. They walked me through the steps needed to run a new power wire (Apparently Audi never ran a 12V power line for the stock radio!) They also were able to tell me which specific wires would be used and what ones I didn't need. Make sure whenever installing a new stereo that you install the shielding AFTER you are done with the wires! Or you'll end up with 5 stitches like me.

Pros: Crutchfield's superior knowledge of their products, the ease of install and willingness to walk me through adding a wire to a fuse box.

Audi A3 Install

Written By GG, Minneapolis, MN on Monday, August 12, 2013

Crutchfield Customer Review (What's this?)

This worked well on my 2006 Audi A3 with the Concert stereo- I installed a Kenwood head-unit and it worked fine. Note, however that a few wires will not come through- neither the illumination nor switched power come through. I had to go to the fusebox to hard wire switched power- otherwise it would not have powered my deck. Used this with an Axxess ACSW-1 to control my head-unit with the steering wheel control. Everything worked just great- I'm very pleased.

Pros: Works well... except...

Cons: No switched power

Product works great, but installation was difficult

Written By NicoleZ, Houston, TX on Tuesday, July 09, 2013

Crutchfield Customer Review (What's this?)

The product itself works great, but the instructions for installation in an 2003 Audi A4 need to be updated. I was confused when the position of the wires in the adapter did not match the wire orientation in the existing harness. I called customer support and they talked me through it in no time at all... and explained that several of the connections that the instructions specified were NOT needed. The live customer support is amazing- it would be nice if the instructions were as explicit.

Pros: Works great.

Cons: I found the installation instructions misleading.

Perfect, no hassle conections

Written By Robert, San Luis Obispo, CA on Saturday, June 22, 2013

Crutchfield Customer Review (What's this?)

Was so simple to hook up Stereo, almost full proof

Pros: Easy and good direction

Cons: Has to strip all the wires down a bit further than they way they were when it came.

Metra 70-1787 Receiver Wiring Harness

Written By Dan, Yakima Wa on Saturday, June 15, 2013

Crutchfield Customer Review (What's this?)

Wiring kit fit for my car. Worked with the Bose System. Easy to connect and easy to follow instructions.

Pros: Connected perfectly.

Cons: One of the wires in the harness was loose. I had to figure out where I was getting noise from. I called Crutchfield and they sent me a new one! No problems since.

Workded on my 2002 TT Bose!

Written By Greg, Los Angeles, CA on Monday, April 22, 2013

I finally got this thing to work on my Audi TT quattro with Bose, I was ready to give up, been browsing forums for days, everybody seem to have different problems but finally got it work and what a great sound! The Bose amp is working everything is perfect. You will need to order a pair ground loop isolator though or when you turn off the car you'll get a loud "pop" in the speakers. You will also need to purchase a wire with fuse clip because you wont get the power from the harness and your HU won't turn on. It's all explained in the documentation that comes with the harness.

Pros: Good instructions, easy to use

Cons: Didn't come with the 12V permanent wire.

Worked Perfect

Written By Anonymous, Seattle, WA on Tuesday, April 02, 2013

Crutchfield Customer Review (What's this?)

This worked perfectly!

Pros: Works

Cons: NA

Doesn't fit Audi A4 2002

Written By MarkH, Basking Ridge, nj on Sunday, December 09, 2012

It fits only to the extent that they snap together with Audi's harness but it doesn't give you full function of the car stereo. A work around for the rear speakers is a must. The color matching of the wires to the car is not one for one either. I installed the Alpine cde 136bt . Step by step instructions were not specific to this car enough to account for the wiring issues encountered.

wrong harness

Written By Audiman, Los Angeles, CA on Saturday, November 24, 2012

Crutchfield Customer Review (What's this?)

Wiring harness received dis not allow for rear speakers or subwoofer connection..had to order different harness

Not all you need with a 06' Audi A3

Written By EddyW, Las Vegas, NV on Friday, November 23, 2012

Crutchfield Customer Review (What's this?)

This might work for certain Volkswagen vehicles, but this harness did not work at all for my Audi A3. You are also going need a CANBUS adapter to go with this harness.

Great and easy to use

Written By AndrewK, York PA on Wednesday, October 03, 2012

Crutchfield Customer Review (What's this?)

I saw a review for a 2002 audi TT coupe. I also have this vehicle and this harness works perfectly fine. I thought it didnt at work but you have to make sure that you use the right PRE AMP outputs. The coupe with the bose system only takes signals from the front left and right ouputs. The rear RCA were not used.

Pros: Colors matched aftermarket unit. Easy to install,

Cons: none

Over all Great job Crutchfield

Written By Ben, Eugene, OR on Saturday, June 16, 2012

Crutchfield Customer Review (What's this?)

This harness worked very well for the installation of a Kenwood KDC-X896 head unit in my Y2K Porsche Boxster. My car has the factory "premium" sound system with amplifier in the front trunk. Only the pre-amp outputs were used as the amp provides all the power to the speakers. The power harness fit tightly. The sound/ pre-amp harness fit but only filled half of the female factory harness, which meant only one side clip locked in (which seemed to be enough). Connecting the the loose wires to the head unit was no problem (I use crimp type connectors and always have w/o problems as long as they stay dry). PAY ATTENTION TO THE NOTES!! as my Bat+ and BAT Switched were reversed as Crutchfield indicated in the note. Install went smoothly, and the unit is working great. Thank you Crutchfield!

Pros: Worked very well, and fit my car

Cons: Pre-amp harness only filled half my factory harness so only one side clip locked in (it is working though).

Pay Attention Porsche Owners

Written By QpQ, Northern Virgnia on Sunday, April 15, 2012

Crutchfield Customer Review (What's this?)

Like a few other folks have mentioned, the Yellow and Red power wires are switched for late 90s and early 2000s Porsches (986s and 987s). Very annoying. However, there was actually a note in the bottom of the wiring guide that was included that mentioned this. However, I of course didn't notice it until everything was soldered and installed. Took it out and re-did it when I realized the mistake. Annoying but functioning now.

The main problem I had with this again seems to be a problem for many people. Why are the rear speaker wires missing?? Crazy. I ripped some wires out of an old harness I was throwing out and inserted them into the right places on this unit and it worked just fine.

In the end, everything is working fine. However, it should have been much easier than this. This thing is overpriced at $25 for the problems it has.

Pros: Swapped Yellow/Red wires is actually noted in the included instructions

Cons: missing rear speaker wires Yellow and Red wires are switched for late 90s-early 2000 Porsches.

Have to modify for 2001 Audi A6

Written By Kevin, Omaha, NE on Sunday, April 08, 2012

Crutchfield Customer Review (What's this?)

My car has a factory amp for the rear speakers and have found out that if you use the RCA cables in this kit the new stereo will make a popping noise when switching between certain opitons like FM, CD, etc. Cut off the rear RCA and plug into new stereo's rear speaker hookups to eliminate this.

Pros: Made well with 1 exception listed in cons.

Cons: My car has a factory amp for the rear speakers and have found out that if you use the RCA cables in this kit the new stereo will make a popping noise when switching between certain opitons like FM, CD, etc. Cut off the rear RCA and plug into new stereo's rear speaker hookups to eliminate this.

Great harness if you know how to hook the power wire

Written By Guyle, michigan on Tuesday, April 03, 2012

Crutchfield Customer Review (What's this?)

Great harness. One thing to note is in my 2003 Audi a4 the red wire did not serve a purpose in a harness. You must run the red wire from your head unit to the fuse box or some other power source. I used fuse 37(windshield wiper fuse)


Written By Adamk, Nepa on Saturday, March 31, 2012

Crutchfield Customer Review (What's this?)

Good easy to use harness

Good, but 1 wire wrong

Written By Close...., Lexington, KY on Wednesday, February 15, 2012

Crutchfield Customer Review (What's this?)

I've used this brand of harnesses several times, and they are always pretty solid. In this case, the switched power and battery power were backwards for my 2001 Porsche 911. I had to use a meter to figure out the right ones.

Pros: Good directions. Easy for a reasonably skilled installer to follow.

Cons: Power types swapped.

Metra 70-1787 Receiver Wiring Harness

Written By Anonymous, queen creek,AZ on Friday, January 20, 2012

Crutchfield Customer Review (What's this?)

works great. came with everything I needed.

Not compatible with Porsche 911 (996). Ugh!!!

Written By Gordie, Bellingham, WA on Thursday, December 29, 2011

Crutchfield Customer Review (What's this?)

No connection for speakers, only power etc. Waste of money. Installing a Kenwood stereo . Very unsatisfied with this harness. May be the last time I purchase from Crutchfield.

UPDATED 1/3/12: After calling Crutchfield for support I got it to work. Thank you.

I would like to change my review from 1 to 5 stars. :0)

Cons: No connection for speakers, only power etc. Waste of money. Very unsatisfied. May be the last time I purchase from Crutchfield.

Not all you'll need

Written By Ben B, Tunkhnnock, PA on Tuesday, July 26, 2011

Crutchfield Customer Review (What's this?)

This harness will get you started. The 12V switched power in the harness had nothing on the car side to power on the radio. I eventually tapped into a wire on the back of the fuse box for this source. I believe the factory radio works off a CAN bus data signal. Past that, I also needed to purchase a SVEN4(additional $$) to get rid of speaker pop noise caused by the factory Bose amp turning on. Then I had to try and fit all the wiring and the SVEN4(which is roughly the size of a VCR, exaggeration) into the dash so the head unit would fit. The dash kit was then modified so the trim ring for the head unit could be used, making it more secure and cleaner looking. Most troublesome install I've ever had in 10 years. Crutchfield support was little help for this vehicle.

Not all you need for Audi A4's

Written By T Buckets, Gilbert AZ on Friday, July 08, 2011

Crutchfield Customer Review (What's this?)

According to a local Scottsdale Car Audio store (Who works on all years of Audi's straight from the local dealerships here in AZ) the A4's need a LOC or crossover control to plug into the aftermarket deck's rear speaker wires and then cut off the rear rca's on this adapter and hook those wires into the crossover control. Then it can turn up and control the rears. The one crutchfield sent to me is made by PACaudio. It with this harness works great! The crossover is huge and has to be smushed way back behind my HU.

Metra 70-1787 Receiver Wiring Harness

Written By thomas, South Jersey on Wednesday, June 15, 2011

Crutchfield Customer Review (What's this?)

I got this for my 99.5 A4, and it made the install easy, however there's no wiring for the rear deck speakers. The only way to use your rear speakers is to hard wire them to the actual harness, which, in my opinion, defeats the purpose of the adapter.

[Editor's Note: Our Technical Department has emailed you with instructions. The rear connections are on a separate included harness.]

02 Audi A4 No rear speakers

Written By Tbuckets, Gilbert, AZ on Monday, June 13, 2011

This has been the hardest and longest wire install for any car I've done... Most of it because of they way Audi set their stock radios. But this harness is supposed to hook up the rear speakers to my deck and it promises the rear speakers will work. But with everything hooked up correctly, the rears are barely even audible even with the volume cranked way up. The tech on the phone said I will have to cut and splice at the factory plug and at the stock rear amp to bypass the amp... This is a lot of work. It should still power the rear amp and is a bummer that I have to tear my trunk to bits just to get the rears to work.

Perfect Harness

Written By RussCuss, Scottsdale, AZ on Thursday, February 10, 2011

Crutchfield Customer Review (What's this?)

This wire harness was so easy to hook up. All the color's matched my after market cd
player. Just had to plug the RCA into the cd player to get the rears to work. Make sure you
tape off your extra wires for your rears on your after market cd player. All in all very easy. I will
buy from CrutchField forever now.

Metra 70-1787 Receiver Wiring Harness

Written By jason, greenwood, indiana on Sunday, September 26, 2010

Crutchfield Customer Review (What's this?)

97 Audi A4 - hooked up perfect no problems

1999 A6 with Bose System

Written By Danny, Columbia, SC on Saturday, February 06, 2010

Crutchfield Customer Review (What's this?)

Harness worked great with my 99 A6 with the Bose system. The only issue is that I now
get a popping sound from speakers (sometimes quiet, sometimes loud) whenever I
change sources or even between stations or CD tracks. I've read that this is due to the
way the Bose amplifier is wired up. I do however have FULL functionality of both FADE
and BALANCE. All reviews I read said I would forfeit these if I went to an aftermarket unit,
but I have no issues. Also, I'm using an Alpine CDA-105. (also purchased from CF).
Overall, good product. My only beefs with my setup is due to my car's factory system.
Can't fault this harness for that.

Does not work for an Audi TT coupe

Written By Mark, Delaware on Thursday, January 21, 2010

Crutchfield Customer Review (What's this?)

Both the Radio installation kit and this wiring harness do not work with a 2002 Audi TT coupe. I have never had these issues with equipment from Crutchfield. I gave 2 stars since I believe I can move the pins around to enable this harness to function, but I should not have to do this. Now I have to try to find out what the factory pin out is so I can adjust this harness.

This should not be listed on Crutchfield as "This item Fits".

2006 Audi A4 (non-Bose)

Written By Nathan, Missouri on Tuesday, January 05, 2010

Crutchfield Customer Review (What's this?)

THIS REVIEW IS FOR A 2006 AUDI A4 (non-Bose)

For anyone else that may need a harness for an aftermarket stereo Crutchfield is great. Keep in mind that you MUST run the ignition wire (red) to an ignition power source such as the windshield wiper fuse. The factory Audi stereo powers on using a different method. Even though the wiring harness from Crutchfield has a red wire dont use it. If you call Crutchfield's tech number they will tell you to run the wire and splice it into your windshield wiper fuse (fuse 36). This should be a 30 amp fuse.

This has been by far the toughest car to put a head unit in but afterwords the results are well worth it.

1998 Audi A6 with BOSE - Worked with NO PROBLEM

Written By Christopher, Philadelphia, PA on Thursday, October 29, 2009

Crutchfield Customer Review (What's this?)

I have owned several Audis over the past 10 years, luckily all the harnesses being the
same was helpful. Every Audi I have owned has had the "Premium Sound" package. I've
had an 84 4000, 87 5000, 89 200 wagon, and now the 98 A6. I was a little hesitant to put
this stuff together myself, especially in such a newer car, but I did it and it worked fine. ALL
of the factory speakers in my A6 are working, even the factory sub. There is NO reason to
pay the big chain stores the $175 that it would cost to have them "hard wire" anything into
your Audi. If you're Audi has the Bose system, make sure that the Blue Wire is matched up
and the deck you're putting in has two RCA outputs on it, this way, all of your speakers will
work. The only things that I lost after this was blanace and fade. But it sounds fantastic
without that.

Thank you Scooter for pointing me in the right direction and saving me a ton of money!!!

Harness wires were not in the correct order

Written By Kevin, Houston, TX on Wednesday, October 28, 2009

Crutchfield Customer Review (What's this?)

I'm not an expert in radio installations, so I do not know if this is typical, but the placement of the connectors in the wiring harness did not match the location of the connectors in my car (2004 Audi TT Roadster). It took pliers, the schematics from my factory radio, and about 20 minutes of trial and error to reconfigure the placement of the pins in the harness. (Like I said, I am not an expert in radio installations). Aside from that, the harness works as one would expect it to work.

Boxster problem

Written By R, Hawaii on Wednesday, March 25, 2009

Crutchfield Customer Review (What's this?)

This harness as-is will probably not work for a Boxster. My 2000 has the factory installation with speakers in the door. The Alpine deck I wanted to put in from another car did not have the RCA line level outputs, and cutting up and attaching wires sent full power from the Alpine amp (rather than line level from a pre-amp) into the factory amp. It was also two channels rather than the four available on the factory amp, so no door speakers, no fader.

I think the Kenwood Excelons have the necessary outputs. That's just the red connector! The black connector had connections in places probably not needed as well.

I'll probably get an Excelon.

Problem for Porsche Boxster

Written By englishgrok, Mountain View, CA on Monday, February 02, 2009

After I installed my JVC Arsenal KD-AHD39 using this wiring harness, I found that the radio worked well but lost all the settings when it was powered off, which was a real pain. I concluded this was a problem with the wiring harness and contacted Crutchfiled who confirmed that for the Porsche the power wires had to be reversed. I was disappointed that I only found this out after I had installed the unit and found the problem.

Good luck with rear speakers

Written By Kevin, Madison, WI on Saturday, November 15, 2008

Crutchfield Customer Review (What's this?)

This wire harness comes with good instructions and what seems to be a good quality harness. My only problem is like another posted said, the rear speakers are preamp outputs that go to your deck. I was never able to get my rear speakers working correctly on my 1996 Audi A4 so after a couple hours of troubleshooting I gave up and just ordered after market speakers for the rear and will run wire back to them.

Metra 70-1787 Receiver Wiring Harness

Written By jtpar24, St Petersburg, FL on Sunday, November 02, 2008

Crutchfield Customer Review (What's this?)

Just what you would expect from Crutchiefld, even though I didn't buy stero
from them I still got top notch service. Told them what I needed and that's
exactly what I got....Receiced my harness in two days and had my stero
installed that day....thanks again..

Good, nor Great

Written By Sneed, Manistee, MI on Saturday, March 01, 2008

Crutchfield Customer Review (What's this?)

This wiring harness is just like any other that you would buy. When i got mine a few of the wires had fallen out of the plastic harness it's self, but they were easy to click back into place. One thing that i didn't like was the fact that that there are no speaker wire connections for your rear speakers (there were only rear amp outputs). I cannot use the fade on my CD player with the connection like that. Other that that, pretty much just a normal wiring harness.

Hands-on research

What's in the box?

Download owner's manual

  • Receiver wiring harness
  • OEM Amplifier harness
  • 40" Separate red wire
  • Fuse tap

Product Research


Crutchfield Wiring Harness: Crutchfield wiring harnesses prevent 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 and 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, and accessories are not included and sold separately. Please see the Accessories tab for recommendations and 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 vehicles may require bypassing the vehicle's factory amplifier (in another location from factory radio) or hardwiring certain connections. If your vehicle is equipped with factory steering wheel controls, an additional adapter is required and sold separately.

Receiver Recommendation: It is recommended that this wiring harness be used with head units that have front and rear RCA line outputs. If using a receiver with only one pair of line outputs, you will need to add Y-adapters and you will lose front-to-back fader control. If you have questions, please contact a Crutchfield advisor at 1-888-955-6000.

Wire Code Chart:

Harness #1 Power/Front Speakers

Wire Color Function
Red * +12 Volt Accessory
Yellow * +12 Volt Constant
Black Chassis Ground
Blue Power Antenna
Orange Illumination
White Left Front Speaker +
White/Black Left Front Speaker -
Gray Right Front Speaker +
Gray/Black Right Front Speaker -

* The function of the Red and Yellow wires is reversed for 1997-2002 Porsche Boxter and 1999-2001 Porsche 911

Harness #2 Factory Amplifier

Wire Color Function
Blue/White Amplifier Turn-On
White RCA Left Front Amp Input
Gray RCA Right Front Amp Input
Green RCA Left Rear Amp Input
Violet RCA Right Rear Amp Input

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