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Metra 70-1857 Bypass Harness

Allows you to connect a new car stereo in select Bose®-equipped 1990-96 GM vehicles

33 Reviews | 2 questions - 2 answers

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Our take on the Metra 70-1857 Bypass Harness

Metra's 70-1857 bypass harness lets you replace the factory radio in select Bose®-equipped 1990-96 GM vehicles using the existing wiring and connectors. This harness bypasses the remote tuner in certain vehicles, while retaining use of the Bose® audio system. Warranty: 1 year.

Metra's 70-1857 bypass harness lets you replace the factory radio in select Bose®-equipped 1990-96 GM vehicles using the existing wiring and connectors. This harness bypasses the remote tuner in certain vehicles, while retaining use of the Bose® audio system. 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.

Very nice install used on 91 Corvette ZR1 to replace Bose system.

Anonymous, Conroe TX

What's in the Box:

  • Receiver wiring harness (includes antenna cable)

Metra 70-1857 Bypass Harness Reviews

Average Customer Review(s):

(33 Reviews)

Metra 70-1857 Bypass Harness

Anonymous from Conroe TX on 9/22/2017

1991 Chevrolet Corvette
Crutchfield Customer Review (What's this?)

Very nice install used on 91 Corvette ZR1 to replace Bose system.



Metra 70-1857 Bypass Harness

don from PINEY FLATS, TN on 9/4/2017

1994 Chevrolet Corvette
Crutchfield Customer Review (What's this?)

Works as expected, I failed to read the directions carefully, but a quick call to customer support put me on the right track, the information is there just read it. I would have given 5 stars, except for an annoying pop when the unit is turned off and on, seems to be related to the power antenna, unhooked all the grounds in the kit, the radio still worked, but still popped, unhooked the frame ground on the antenna, still worked, still popped, puzzling. otherwise happy, radio sounds great all functions work great, easy hookup.



Metra 70-1857 Bypass Harness

KD from Denver, CO on 8/7/2017

1990 Chevrolet Corvette
Crutchfield Customer Review (What's this?)

Worked well for my 1990 Corvette. My only complaint is with the Crutchfield instructions themselves, they said that my amp (well the controller for the amp at least) was in the rear of the car when actually it was behind the glove box. Crutchfield support figured this out fairly quickly after I got on the phone with them. Also, this harness did not provide support for my power antenna or dimmer. This is probably also due to limitations with the car's existing wiring I imagine though.

Pros: Worked great for my 1990 Corvette w/ Bose

Cons: Very long cable, nice when needed but cumbersome when not

Metra 70-1857 Bypass Harness

Anonymous from Greensburg, PA on 6/12/2017

2008 Chevrolet Avalanche
Crutchfield Customer Review (What's this?)

Needed for install of radio on a 1991 Corvette with the factory Bose system (unless you're an idiot and actually cut the factory wiring). All connections worked fine. Only issue is the harness is very, very long, just requires you to find a place to store all the excess wiring. I placed my excess where the actual tuner was mounted.



Metra 70-1857 Bypass Harness

Jon from Phoenix AZ on 5/22/2017

1996 Chevrolet Corvette
Crutchfield Customer Review (What's this?)

Works great, used it on my 96 corvette with the Bose.

Pros: everything you need if you have a Bose in your car


Metra 70-1857 Bypass Harness

Stanley from Illinois on 5/13/2017

1993 Chevrolet Corvette
Crutchfield Customer Review (What's this?)

In the end I decided to bypass the bose altogether. The kit provided the much needed antenna lead and plenty of wore to boot. A wide buy.



A must have!

Chris J from West Saint Paul, MN on 8/8/2016

1996 Chevrolet Corvette
Crutchfield Customer Review (What's this?)

I actually installed this into my 1996 Corvette convertible not the coupe. If your older C4 Corvette has the Bose system and you want to keep the Bose speakers this is a must have! The only knock is the lack of detailed instructions that come with this harness so I will try to help. The radio in the late model C4 Corvettes is actually more or less a "dummy" unit. The actual tuner for the vehicle is tucked behind the passenger seat under the rear storage container. This harness is designed to run from your new aftermarket head unit back to the wiring harnesses hooked up to the factory tuner. The vehicles stereo antenna lead is also located behind the passenger seat near the stereo tuner. Basically you unplug all of the harnesses going into the stock stereo tuner and install them into this aftermarket harness along with the factory stereo antenna lead which is tucked away closer to the rear of the passenger seat inside the storage compartment (I had to reach in and feel for it to find it). The actual hook up of this harness to your new aftermarket stereo is a breeze. While some folks on here are unhappy with the length of the wires I found that if you do a thorough and proper installation you will use the majority of the wires length. I must say that I was somewhat skeptical about how well this wiring harness would work and difficulty of installing it but after my installation experience it was surprisingly easy and provided me with the results that I was looking for.

Pros: Simplicity and ease of installing the harrness

Cons: Lack of good detailed instructions

Bose bypass harness works great!

Thomas from Grand Rapids, MN on 8/1/2016

1994 Chevrolet Corvette
Crutchfield Customer Review (What's this?)

harness worked great and just as described. Allowed me to connect a new receiver to my existing Bose Gold amplified speakers. Could use a bit more documentation on how to connect and would benefit to note that PAC-SN1 ground loop isolators should be used to eliminate power on and source change pop from factory amps.

Pros: allows connection to factory speakers

Cons: no notes on using ground loop isolators

Bose harness

eric from Louisiana on 7/30/2016

1995 Chevrolet Corvette
Crutchfield Customer Review (What's this?)

Great plug and play product, just a little long for corvette.

Pros: easy assembly and instructiins

Cons: to long for a corvette

Great Working product,

Tazman9344 from Port Orchard, WA on 4/29/2016

1992 Cadillac Seville

Ordered this to make my aftermarket stereo work with my existing Bose system, and it works fantastic. the sound is still great, and now an old car has a new class of stereo.



Easy to install

Sam from Maryland on 12/12/2015

1996 Chevrolet Corvette
Crutchfield Customer Review (What's this?)

Was very easy to install and had plenty of length to reach where I needed it to.

Pros: Long wires Well labeled Easy to install

Cons: None

Does the job

Gusvette from Oregon on 10/9/2015

1996 Chevrolet Corvette
Crutchfield Customer Review (What's this?)

Great interface, but 6' of extra cable

Pros: Works perfectly

Cons: I had about 6' of extra cable when finished. A cable designed for specific autos would be great.

Must have for replacing Bose

jm2088 from Alabama on 9/25/2015

1994 Chevrolet Corvette
Crutchfield Customer Review (What's this?)

This was a huge help with replacing the Factory Bose unit in my 94 corvette. It has all of the connections you need. There are no instructions but basically you need to check out the instructions at ZIP corvette. You will need to run the wires along the passenger side of the car. (Zip recommends removing the seat but I didn't need to do that. It's a big job but well worth it.

Pros: Good cost. Everything you need for the job

Cons: None - This is a weekend project but that has nothing to do with this harness.


pumasixtynine from grand terrace, ca. on 3/31/2015

Crutchfield Customer Review (What's this?)

Awesome, works as described! fast shipping!

Pros: Perfect fitment!

Cons: None!


RANDY from Texas on 1/18/2015

1994 Chevrolet Corvette
Crutchfield Customer Review (What's this?)



Cons: N/A

1993 Caddy Radio project

dtb from Edgewater,Fl on 9/14/2014

Crutchfield Customer Review (What's this?)

Ordered the wrong wiring harness even after talking to a consultant that advised me of a possible error I had made but I didn't listen to him. Great products/Great people/Great Company!! Have the right part now after swapping out. I have dealt with Crutchfield before on other products & vehicles and cannot put into words how impressed I am with all aspects of this Company. You will always have my business and I am recommending your Company to all my friends and family . Your Professionalism, Product support, Outstanding Staff are what is all about. Wish the rest of America would figure that out! Great job!!

Pros: Professional, Knowledgeable Product & Customer Support Outstanding ,

Cons: None!

Metra 70-1857 Bypass Harness

Andy from Pelham nh on 9/13/2014

1992 Chevrolet Corvette
Crutchfield Customer Review (What's this?)

A well made harness but it was only a little helpful and I only used some of it . I believe this was because of my vehicle type which is a 1992 corvette with a Bose system but on another Chevrolet product I think it would be fine

Pros: It had some parts necessary to connect to existing connectors

Cons: I still had to buy wire and wire up all the speakers

Defintely easier install

Tom from Evansville, IN on 7/27/2014

Crutchfield Customer Review (What's this?)

Good Idea

Pros: All wires were correct. Nice to be able to plug into the harness without running all new wires and I was able to use the original BOSE Amps and speakers.

Cons: The wiring only needed to be about 5 to 6 feet long and was probably 20 feet long. The RCA and Antenna wires are already finished with plugs on both ends so I didnt' want to cut those. Just wound them up, zip tied them and put them under the dash.

Not quite the way I thought it would work

OD from Baltimore, MD on 5/30/2014

1995 Chevrolet Corvette
Crutchfield Customer Review (What's this?)

While supposedly this was meant for my '95 corvette, and the instructions were fine, it somehow didn't quite fit the way I envisioned it. The product itself was great, and very long which turned out to be useful.

Pros: good product, worth the money

Cons: didn't fit the way I thought it would

Metra 70-1857 Bypass Harness

dude from Farley, IA on 5/19/2014

Crutchfield Customer Review (What's this?)

I just want to say thank you so much to the crutchfield team of techs that helped me install my stereo I had to call a couple of times for help . My stereo sounds excellent once again thank you . I have since recommend crutchfield to my friends .

Pros: Great selection of product at a great price .

Cons: Can't say anything bad .

Metra 70-1857 Bypass Harness

Steve from Bridgeview Il. on 4/7/2014

1990 Chevrolet Corvette
Crutchfield Customer Review (What's this?)

This adapter is the perfect answer to the problem of connecting to a bose amplified speaker system. It would be a bargain at twice the price.

Pros: There really is no better way to connect an aftermarket head unit to a factory bose system. super easy plug and play install.

Cons: The cables can be much to long for some applications and become difficult to package.

Did everything as advertised

gliot1 from Lake in the Hills, IL on 3/17/2014

1996 Chevrolet Corvette
Crutchfield Customer Review (What's this?)

The cable itself was awesome. The directions only included a wiring diagram; no instructions. In the case of a Corvette Bose system, this cable is intended to connect to the hidden pre-amp behind the seat. In my case I believed it connected into the wire harness behind the head unit, but the connectors would not match up. Nothing in the included paperwork indicated this. I will say, though that one call to the Crutchfield Help desk solved the issue in under 2 min. The tech knew immediately the specifics of the '96 Corvette and pointed out where the cable connected. It was very refreshing to have someone pick up the phone immediately and speak clearly, in proper English as well! High five to Crutchfiled!

Pros: This cable mates to the stock Bose system with perfection. I would have given 5 stars for better instructions

Cons: The instructions tell you little and are simply a wiring diagram.

Metra 70-1857 Bypass Harness

Anonymous from Clayton, CA on 10/21/2013

Crutchfield Customer Review (What's this?)

Harness is 17 feet long which may be required for some applications. 6 feet length would have worked for my application. The power leads can be cut down but the amplifier leads would be more difficult and you would require a shorter antenna lead.




Jackie from Wellesley, MA on 5/24/2013

1991 Chevrolet Corvette
Crutchfield Customer Review (What's this?)

Ordered this for my HD pioneer, for my 91 Corvette base model with Bose system. This is allowing the faders to work. It simplified everything!!! Not confusing at all either. Troy was very helpful in finding what i needed. Thanks!!!!

Pros: Simple, organized, color-coded, problem solving


Great adapter!

Vette Guy from Alexandria, VA on 4/21/2013

1991 Chevrolet Corvette
Crutchfield Customer Review (What's this?)

Perfect adapter and quality connections. Be prepared to have a lot of wire. It weighs a few pounds, and is enough wire to span the length of a SUV!

Pros: Perfect fit

Cons: A lot of wire that you'll have to hide as there is no cutting the RCA cables. I estimate 10' of wire.

Must havve

csthews from TX on 4/19/2013

1995 Chevrolet Corvette
Crutchfield Customer Review (What's this?)

Without this, the installation would have been a nightmare

Pros: Easy install. Great instructions and phone support

Cons: None

Works!!!!! Not and really easy

Fast & Loud from Phila. Pa. on 4/8/2013

1992 Chevrolet Corvette
Crutchfield Customer Review (What's this?)

Very good Quilty wires and plug.........

Pros: Lots of wire!!!

Cons: Way to long of an antena wire does not need to be 10 foot long maybe 6 foot at the most!!! the problem is you have to make the dash fit together but it did you have to just have to think outside the box and you'll find a spot to hide the wires........

Metra 70-1857 Bypass Harness

doug16 from ohio on 11/21/2012

Crutchfield Customer Review (What's this?)

didnt come with line filters

Pros: long wires

Cons: no line filters

Every thing I needed

Maurice D from Cedar Rapids IA on 7/16/2012

1994 Chevrolet Corvette
Crutchfield Customer Review (What's this?)

After a couple discussions with the tech at Crutchfield, the harness was pretty easy to figure out, worked great.

Pros: All conections to were well researched by Crutchfield.

Cons: none

Works great

noelia_10 from Manville N.J. on 6/13/2012

1992 Chevrolet Corvette
Crutchfield Customer Review (What's this?)

Installed on 1992 corvette with Bose system worked excellent. Attached aftermarket head unit to bose speakers. Only down fall to much wire for my application should be more tailored to vehicle.

Pros: Worked as intended

Cons: To much wire for application

Wire harness

Ted from Piqua Ohio on 5/22/2012

Crutchfield Customer Review (What's this?)

Had no instructions

Pros: None

Cons: Need info to hook up

Crutchfield response on 5/30/2012 Thanks for your comment. This adapter works in many different vehicles, and we do offer complete instructions for most of them. If you need information that doesn't come with your product, our tech support specialists can provide it over the phone.


tommy c from new york on 5/1/2012

Crutchfield Customer Review (What's this?)

A helpful piece for and easier install. I used it in my 92 cadillac eldorado with bose!

Pros: Sounds and works well!

Cons: when turning the radio on makes a thump sound. but other than that pretty clear!


aaron from pontiac il on 2/25/2012

1994 Cadillac Eldorado
Crutchfield Customer Review (What's this?)

helpful easy to install but there is some unwanted noise the most difficult stereo ive done yet 1994 cadillac eldorado with bose stereo

Pros: stereo works now

Cons: lousy sound


Hands-on research

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
Black (thick cable) Antenna Cable
Red +12 Volt Accessory
Yellow +12 Volt Constant
Black (3) Ground
Blue Power Antenna
White RCA Left Front Channel
Gray RCA Right Front Channel
Green RCA Left Rear Channel
Violet RCA Right Rear Channel


  • There are three ground wires in the harness; all three should be connected to the new receiver's ground lead.
  • The male RCA plugs on the harness are plugged into the front and rear line-level outputs on the new receiver.

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

Q & A

Customer Q&A

Crutchfield asked  
Why did you buy this?

Was recommended by Chad for my installation at no charge. [ B  Oct 04, 2017 ]
Recommended by advisor [ Richard  May 01, 2017 ]
Site recommendations [ Stanley  Apr 28, 2017 ]
needed to easily interface after market reciever into specific vehicle and retain as is vehicle wiring harness [ William  Feb 20, 2017 ]
this eliminates problems with old Bose system [ christopher  Dec 13, 2016 ]
adapter cable for stereo, needed and good price [ Kim  Jun 28, 2016 ]
came with kit [ DENNIS  May 15, 2016 ]
New head unit for 1991 Corvette ZR-1 [ PETER  Jan 26, 2016 ]

2 questions already asked

If you purchased the product from Crutchfield, feel free to contact our Tech Support team. They can walk you through the settings on the product and see if there may be a fix. Our toll-free Tech Support number is printed on your invoice, and is also available under the "My Orders" tab in the "My Account" section of our website. If you did not purchase the unit from Crutchfield, then you may want to contact the manufacturer. You can also post your question in our forums: Or try our online support center: [ Krissy  Aug 01, 2016 ]  Staff
You can check to see if this will fit your vehicle by using our Outfit My Car tool: For additional 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 21, 2016 ]  Staff

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