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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
Item # 120701857 | MFR # 70-1857
$34.99 Earn up to 35 Rewards points
Our take on the Metra 70-1857 Bypass Harness by Crutchfield's Zak Billmeier
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.
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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:
|Black (thick cable)||Antenna Cable|
|Red||+12 Volt Accessory|
|Yellow||+12 Volt Constant|
|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.
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Why did you buy this?
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: http://community.crutchfield.com. Or try our online support center: http://crutchfield.custhelp.com/app/answers/list/kw/. [ Krissy Aug 01, 2016 ] Staff
You can check to see if this will fit your vehicle by using our Outfit My Car tool: http://www.crutchfield.com/car/carselector.aspx 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