Metra 70-1786 Receiver Wiring Harness

Connect a new car stereo in select 1994-2008 Chrysler, Land Rover, Mercedes, and Saab vehicles

Item #: 120701786

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54 Reviews

Installation gear for most cars

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Metra 70-1786 Receiver Wiring Harness

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'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 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 70-1786 Receiver Wiring Harness Reviews

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Easy clip on

Written By Ryan, Missouri on Sunday, October 04, 2015

Crossfire 2005 wires fit perfectly

Crutchfield comes through.

Written By Kris, Maryland on Saturday, September 12, 2015

Crutchfield Customer Review (What's this?)

Crutchfield makes it easy to get parts I need.

If recommended by Crutchfield, then its a simple swap

Written By Matt, Toronto, Ontario on Monday, September 07, 2015

Crutchfield Customer Review (What's this?)

Fitment and product matching was perfect as per Crutchfield's recommendation.

Pros: Wiring layout on package. Product seems the be well built

Cons: Possible extensions must be made if using a line-output converter.

Metra 70-1786 Receiver Wiring Harness

Written By Anonymous, New York on Sunday, August 30, 2015

Crutchfield Customer Review (What's this?)


Excellent Item but vague instructions

Written By halligood, Pennsylvania on Sunday, April 19, 2015

Crutchfield Customer Review (What's this?)

This was exactly the item that I needed, but it took me a day or so to figure it out. I had quite a few wires that were not needed and had to be tied off. Since it was my first attempt at such a task, I attribute my ignorance to inexperience. Since installing, I have had a half dozen friends want to modify their vehicles exactly as I did. That is a compliment towards the effectiveness of your product.

Pros: perfect interface once you figure out the wiring.

Cons: None really. If I had to do this again my 2 day project would be a 30 minute project.

Great Products

Written By MM, Cape Charles, Va on Wednesday, April 08, 2015

Crutchfield Customer Review (What's this?)

Great product, perfect fit! My favorite thing is that Crutchfield sends a MasterSheet with instructions and diagrams!

Meta harness

Written By DEEBEE, North Carolina on Sunday, February 22, 2015

Crutchfield Customer Review (What's this?)

Easy to install, does what it is supposed to do. I had a setting off in my Kenwood which when synched to iphone6 only played music on front speakers. Called the team at Crutchfield and it was just a setting change not the harness. Crutchfield, your support is the best

Pros: Easy to install and it works

Cons: Absolutely none

Perfect Fit

Written By Mr. G, Baltimore, Maryland on Monday, February 09, 2015

Crutchfield Customer Review (What's this?)

This harness fit perfectly as part of my after market sound system per the advice of the experts at Crutchfield. I was thoroughly satisfied with the easy fit between the Pioneer CD receiver and the factory Bose system.

Pros: Excellent fit, easy connection.

Cons: Happy to say no cons!

Easy to use

Written By Jason, Cartersville, GA on Friday, January 23, 2015

Crutchfield Customer Review (What's this?)

This product worked perfect with my set up.

Pros: Great product

Cons: None

Adapter for 01 Mercedes SLK

Written By MichaelT, California on Friday, January 09, 2015

Crutchfield Customer Review (What's this?)

Perfect fit. Made installation quick and easy.

Metra 70-1786 Receiver Wiring Harness

Written By t3ragtop, Ohio on Tuesday, December 30, 2014

Crutchfield Customer Review (What's this?)

This wiring harness adapter made my installation painless and left my car's wiring intact. The wiring diagram that Crutchfield sent by email made it easy to connect the head unit's wiring correctly and without issue.

Pros: The proper connections make a neat and tidy installation.

Metra 70-1786 Receiver Wiring Harness

Written By Anonymous, Rialto Ca 92376 on Monday, November 17, 2014

Crutchfield Customer Review (What's this?)

Easy to connect

Pros: Best thing ever

Cons: No con

Excellent product

Written By Anonymous, the Washington, DC Area on Thursday, November 06, 2014

Crutchfield Customer Review (What's this?)

This harness made adding my new head unit to my Mercedes. Super easy and works great.

Metra 70-1786 Receiver Wiring Harness

Written By Mike R, Boston, MA on Thursday, October 16, 2014

Crutchfield Customer Review (What's this?)

Where the heck were these things years ago? These wiring harnesses are great for a neat and professional installation that allow switching back to the original setup if needed (classic car, keep original radio, etc.). Take your time, use soldered connections sealed with shrink tubing and you'll have a super setup.

Pros: Instructions for my specific application were not available. Hunting around in the various forums gave me enough information to make it work the first time.

Cons: Lacked a "Master Sheet" for my application (1999 Mercedes SL500)

metra 70-1786 harness

Written By Avi, Ashland OH on Wednesday, September 24, 2014

Crutchfield Customer Review (What's this?)

Perfect fit. Easy to install. Free with head unit purchase.

Pros: Perfect fit

Cons: None

Metra 70-1786 Wiring Harness

Written By EugeneB, Knoxville, TN on Friday, August 22, 2014

Crutchfield Customer Review (What's this?)

This harness was a perfect fit and easy to wire to the harness that came with my radio. The wires were color coded to match the color of the Alpine harness, making the wiring job easy. It would have been better if the instructions had said to plug the front speaker jacks into the front ports, and the rear jacks into the subwoofer ports on the radio. My Crossfire does not have rear speakers, it has rear subwoofers.

Pros: color coded wires

Cons: none

Works great for 2004 Chrysler Crossfire

Written By MBD, Texas on Saturday, July 26, 2014

Crutchfield Customer Review (What's this?)

I got this for a 2004 Chrysler Crossfire, which is essentially a Mercedes since it was built in Germany by Mercedes for Chrysler. which was owned at the time by Daimler (Mercedes). Anyway, this connector made the job installing my stereo (Clarion M502) much easier since it doesn't require the cutting or splicing of wires. You just wire this connecter to the connector that plugs in the back of the new stereo and plug it in.

Pros: Simple & Doesn't require cutting any wires.

Cons: Nothing really except I saw where the materials that this is made of of is known to cause cancer in the state of California. Good thing I'm in Texas.....LOL.... Seriously why would they make anything out of lead paint or whatever. I just washed my hands after touching it and now I'm enjoying my new Clarion Stereo.

plug and play

Written By Doc, Hermiston Oregon on Friday, July 25, 2014

Crutchfield Customer Review (What's this?)

The local shop wanted $300 because I had a Mercedes Benz e430 with a Bose premium system to install the new deck that I already bought. I called Crutchfield they sent me the plug and play wire harness for this price and I had it installed in 20 min. awesome customer service awesome product

Pros: plug and play

Cons: none

Metra 70-1786 Receiver Wiring Harness

Written By Anonymous, warren, pa on Saturday, June 14, 2014

Crutchfield Customer Review (What's this?)

works good but seems like power is low going out of rcas but it does work and easy to hook up

Pros: easy connection

Metra 70-1786 Receiver Wire Harness Review

Written By SteveCP, Sacramento, CA on Monday, May 05, 2014

Crutchfield Customer Review (What's this?)

A simple, easy to use installation harness to provide a professional installation. A necessity in providing a correct, straight-forward installation of an aftermarket radio.

Pros: Takes some of the guesswork out of matching the correct wires to complete your installation without changing the original connector harness in my vehicle. Very nice that Crutchfield makes this available at no charge when purchasing your new radio!

Cons: Not all of the connections and signals match this wiring harness adapter and not all of the Crutchfield provided instructions were accurate to my vehicle. Most importantly, the switched power lead is in the wrong location to use this harness. An additional power lead had to be added.

Metra 70-1786 Receiver Wiring Harness

Written By Carlos, welford on Tuesday, April 22, 2014

Crutchfield Customer Review (What's this?)

Received in a timely manner, and product works great. Also i like the professionalism and how fast the person on the phone found my part.

2001 Mercedes E430

Written By Baro, Renton, WA on Saturday, April 19, 2014

Crutchfield Customer Review (What's this?)

It worked with little bit of work. My 2001 Mercedes E430 didn't have switched power on and dimming wire coming from the car. I had to connect switched on power wire from cigarette plug to make it work. Also I need to get dimming light wire connection from the light switch.

Pros: Plug in

Cons: Didn't connect to my car's switched power on wire.

Game Changer

Written By Jimmy J, Vail, AZ on Tuesday, April 08, 2014

Crutchfield Customer Review (What's this?)

Saved me hundreds on install. Local shops wanted to do a custom install, because Alpine did not show a compatible harness...guess they for got to ask you guys and girls. The harness made it a simple "plug and play"

Pros: Easy diagram to follow. Wired at kitchen table.

Worked well

Written By Uncle Sam, Denver, CO on Tuesday, March 25, 2014

Crutchfield Customer Review (What's this?)

Worked just fine. I was able to remove the pins from this harness using a tiny screwdriver and re-crimp the wires on the stereo harness onto the pins.

Pros: Good quality, wired correctly for the Chrysler Crossfire.

Cons: I wish that harness makers would include a spare set of pins for the harness so that I can make the harness using the radio's wiring loom. When done this way there is no soldering and it works/looks excellently. I ended up pulling the pins from the harness and removing the harness supplied wires to make this happen.

Worked like a charm

Written By RickM, Olympia, WA on Wednesday, February 05, 2014

Crutchfield Customer Review (What's this?)

Crutchfield provided it, free of charge, I connected it to my Alpine unit (purchased through Crutchfield) and it worked beautifully the moment I turned the unit on. This is in stark contrast to a Kenwood unit and harness I purchased from other suppliers, which gave me a hot popping sound every time I changed stations, sources, or songs. Crutchfield gave me the combination of products that worked flawlessly together.

Pros: Easy, fast, it works.

Cons: Nada

Metra 70-1786 Receiver Wiring Harness

Written By Alzonez, 11105 on Thursday, January 02, 2014

Crutchfield Customer Review (What's this?)

Makes life easy!


Written By bserrone, Raleigh NC on Sunday, December 29, 2013

Crutchfield Customer Review (What's this?)

Great fit. Crutchfield made it easy!! The rep loaded my cart with everything I needed. Trust the tech!!

Pros: Easy as pie. Mmmmmm! Pie!!

Excellent Fit

Written By Anonymous, Vancouver, WA on Wednesday, December 11, 2013

Crutchfield Customer Review (What's this?)

Used this in an Alpine install into a Mercedes and it matched the factory connector well. The instructions included said I would have to cut the factory connector but that was not the case. The plugged in with zero modification needed.

Pros: Using this helps keep the factory wiring uncut. Good fit to the factory plug.

Metra 70-1786 Receiver Wiring Harness

Written By Anonymous, Los Angeles, CA on Tuesday, October 29, 2013

Crutchfield Customer Review (What's this?)

Random but this my save you some frustration: If you have a Mercedes 230 SLK (R170), you do not need the rear outputs from the head unit. While this harness has rear RCAs, they don't actually lead anywhere after you connect the Crutchfield harness to the factory harness. It works fine because the signal from the front outputs goes to the car's built-in amp, which powers both front and rear speakers. This can be really confusing because your fader will not work and you might think there's a problem with the rear speakers or wiring. But your fader never actually worked. Who needs a fader in a 2-seat roadster? Also, remember to get posi caps and an antenna adapter.

Pros: Works, simple, easy. Amazing customer service from Crutchfield, that's hands down the best part.

Fits Mercedes well

Written By Troy, Lady Lake, FL on Tuesday, October 15, 2013

Crutchfield Customer Review (What's this?)

Fit perfectly.

Pros: Good quality and fits perfectly

Cons: none

Metra 70-1786 Receiver Wiring Harness

Written By Anonymous, Charlevoix, MI on Tuesday, August 20, 2013

Crutchfield Customer Review (What's this?)

With this plug installation couldn't been easier!


Written By DickF, Naples, FL on Monday, August 05, 2013

Crutchfield Customer Review (What's this?)

Exactly fit my Crossfire wiring

Pros: Perfect fit

Cons: none

Metra 70-1786 Receiver Wiring Harness

Written By Tom, Longwwod, FL on Wednesday, June 19, 2013

Crutchfield Customer Review (What's this?)

very simple to use although the instructions could be a little more detailed.

Receiver Wire Harness

Written By Ron, Ridgeland, MS on Wednesday, June 12, 2013

Crutchfield Customer Review (What's this?)

Harness worked as advertised, however I still had to cut the speaker wires due to the having rca connectors on the end.

This Makes ALL The Difference

Written By Manny, Veradale, WA on Tuesday, June 11, 2013

Crutchfield Customer Review (What's this?)

Changing the unit would not be happening without this harness.

Pros: The only way to go.

Metra 70-1786 Receiver Wiring Harness

Written By Anonymous, Iowa Park, TX on Monday, May 27, 2013

Crutchfield Customer Review (What's this?)

Easy install and work perfectly. Thanks Crutchfield

Receiver wire harness

Written By Mbg319, Fort Scott, KS on Thursday, May 23, 2013

Crutchfield Customer Review (What's this?)

Works great made the installation a breeze. Once I had the harness wired to new receiver it took about 10 minuets to install the receiver.

Pros: Makes the install super easy

Cons: None

it works

Written By nickmang, nashville, tn on Sunday, May 12, 2013

Crutchfield Customer Review (What's this?)

It works as it should, wire coding matched lined up well with car and stereo.

Pros: it's works

Cons: none

Chrysler Crossfire and JVC KD-80BT

Written By RJB, San Antonio, TX on Wednesday, May 01, 2013

Crutchfield Customer Review (What's this?)

This harness made the unit "plug & play".

Pros: It works.

Cons: None.

Perfect Fit

Written By Peterson, Tampa,FL. on Tuesday, March 12, 2013

Crutchfield Customer Review (What's this?)

This was included with the radio I purchased. It was setup to work with my vehicle and the Bose system that was already in the vehicle. I connected the wires to the radio and was able to plug the unit right in when I installed it. Everything works perfectly. The only issue was that there is no accessory power (red wire) in the oem harness. The plug has a spot for it but there was nothing on the vehicle side. I ended up running power from the cigarette lighter supply. This has nothing to do with the harness kit, it is an issue with the car itself. The factory head unit got power from another source.

Pros: Plugs right in and had the rca jacks to plug right into the pre-outs on the head unit. I did not have to connect one speaker wire.

Cons: None

Perfect fit

Written By Alex J., Miami, FL on Thursday, February 28, 2013

Crutchfield Customer Review (What's this?)

This connector was a perfect fit to my Bose amplifier. All the 12 stock speakers are rocking aloud

Cons: None

Perfect Fit

Written By JP, Apollo Beach, FL on Thursday, February 28, 2013

Crutchfield Customer Review (What's this?)

A perfect fit, just plug and play! After reading forum posts and wiring it accordingly (was told to switch a couple of power wires), found out the wiring on this connector was correct all along. So much for 'expert' forum installers..ha, ha. This is the reason to go with Crutchfield and no one else!!!

Pros: Perfect fit for my application

Not so good

Written By Bob B, New York on Friday, January 04, 2013

Crutchfield Customer Review (What's this?)

This harness is not worth the aggravation it caused, even for free. The RCA connectors are too loose and nearly fall off the back of the HU. They made poor contact, leading to excessive alternator noise entering the amplifier loop. I eventually removed this adapter it and replaced it with a higher quality unit that I purchased elsewhere; doing this dramatically reduced the alternator noise. I would give 0 stars if I could. Application was a Mercedes C280 with Bose amp.

Pros: Free with order.

Cons: RCA connectors are very poor quality.

Cant get any easier

Written By Nate, NJ on Saturday, December 22, 2012

Crutchfield Customer Review (What's this?)

Must Must have for land rover if keeping factory speaker system.

Fits R170 SLK

Written By Anonymous, White Plains, NY on Wednesday, September 05, 2012

Crutchfield Customer Review (What's this?)

Like described.

Receiver wire harness

Written By Masi, Costa Mesa, CA on Friday, August 17, 2012

Crutchfield Customer Review (What's this?)

The harness made it easy to make the required connections.

Pros: After making sure that the wiring connections were secure, it will be there forever!

Cons: None

Wrong item-but was fixed

Written By Mark, Jamesport, NY on Monday, April 30, 2012

Crutchfield Customer Review (What's this?)

The wrong item was sent, called Crutchfeild. They immediatedly sent out the correct one, got it two days later and in went the new radio!

Pros: Crutchfield immediatedly fixed problem

Cons: Wrong item

Much Needed

Written By Lee, Newnan, GA on Thursday, February 02, 2012

Crutchfield Customer Review (What's this?)

This product solves connection issues with Euro vehicles when connecting American / Asian head units.I used it in my Mercedes and all the factory speakers and amp now work with the new CD player.

Pros: Easy and accurate connection harness and quality RCA jacks.

Cons: I think the connecting wires could be longer for some applications.


Written By Doug, Seattle on Thursday, November 03, 2011

Crutchfield Customer Review (What's this?)

When I tried to install the radio the harness plugged in OK but the wire match was not exact. After talking to company reps additional wiring was required beyond the harness. One of the suggested fixes was jumpering the power to constant power and just remembering to turn off the radio when I left the car.

Pros: The way Critchfield misled me

Cons: It did not work

Mercedes Advice

Written By Hotmann, Colorado on Monday, October 31, 2011

Crutchfield Customer Review (What's this?)

I have a 2001 Mercedes E320 and this wiring harness fits everything perfect.

Some advice though for Mercedes owners: If the stock connectors don't have a line going into the switched power (red) line on the harness you will have to tie into the cigarette lighter's switched power source. To access this: lift the wood around the shifter knob up (the whole thing with the window controls and everything)so that you can access the two screws that hold the ash tray in place. Unscrew and pull out the ash tray. You will see a yellow/black wire, hook into that with a 8"+ wire and pull it up behind and through the cd slot. Connect that to the switch power wire for the stereo and enjoy.

Pros: Saved me lots of time. Only had to solder the power wires and didn't have to lookup the car's wiring info.

Cons: Nothing.

Mercedes harness

Written By Glenn, Durham on Sunday, October 02, 2011

Crutchfield Customer Review (What's this?)

One of the best things about Crutchfield is supplying a harness such as this one with the purchase of a head unit. Harness was perfect to allow use of the Bose amplifier without needing to read a wiring diagram to splice everything in place. Thanks for saving me a lot of anguish.

Saved some time... but

Written By DanD, Atanta, GA on Monday, April 11, 2011

It plugged right into my factory harness, so that's cool because it's clean and
saves you from having to splice. Unfortunately, the "always on" and "Ignition
on" leads were reversed from those on my car. It took a little investigation to
figure that out.

Also, the left rear speaker connection is flacky, so you should make sure the
connections are good, before you cram all those wires into the dash.


Written By jimp, bennington,vt on Thursday, March 24, 2011

Crutchfield Customer Review (What's this?)

product was as described, easy to self install, product manual not the easiest
to understand, happy w/product and purchase

Real nice

Written By Tim, Vermilion Ohio on Tuesday, March 15, 2011

Crutchfield Customer Review (What's this?)

This harness is very well made, and plugged right in, can't ask for any more
than that

Hands-on research

What's in the box?

Download owner's manual

  • Receiver wiring harness

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 Ground
Blue/White Amp Turn-On
Orange/White Dimmer
White RCA Left Front Channel
Gray RCA Right Front Channel
Green RCA Left Rear Channel
Violet RCA Right Rear Channel

Factory Amp Note: This harness includes RCA connections (instead of speaker wire leads) to connect the aftermarket head unit's preamp outputs to your vehicle's factory amp. Your aftermarket head unit must be equipped with front & rear preamp outputs.

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.

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