Name: Metra 70-1787 Receiver Wiring Harness
Brand: Metra
SKU: 120701787
Price: 27.99 CAD
Availability: InStock
Rating: 4 (116 reviews)

This vehicle-specific wiring harness makes connections between your new car stereo and your car's electrical system.

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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 colour-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.

READ LESS

What's in the box:

Metra 70-1787 Receiver Wiring Harness owner's manual

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

MFR #70-1787C

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Features

Wiring Harness: This wiring harness prevents having to cut your vehicle's factory radio plug when replacing your factory radio with an aftermarket head unit. Simply solder or crimp the 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 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 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 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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4 questions already asked

How do you hook up the rear speakers if there are only front left and front right speaker connections?

frank Jan 28, 2019

4 answers

The rca pig tails are for the speakers. I cut them off and wire it directly to the factory amp.

jesus Jan 30, 2019

I am assuming this is for an Audi. I had to buy a completely separate piece to go with the wiring harness before the stereo would work at all. Cant remember what it was but you have to get it because the rear speakers are on an amplifier and this piece is the only thing that would make the stereo work.

scott Jan 30, 2019

I couldn't honestly answer this...I took it to an installer.

doug Jan 30, 2019

If you purchased the product from Crutchfield, feel free to contact our Tech Support team. 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.

kristina Jan 30, 2019 (Staff)

Good Evening, I have a 199.5 Audi S6 with a bose stereo. It calls for a 70-1785 but this was incorrect and the plugs the car has are a 70-1787. I have the stereo powered up and the amp appears to be turning on but I get no Audio. I see others have had the same issue and needed to change pins. I was just wondering if you have the correct pin locations for this application? Thank you, Eric

eric Aug 05, 2018

1 answer

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.

kristina Aug 10, 2018 (Staff)

I have a 1994 Audi cabriolet and tried to use this adapter with this Pioneer head unit. The black plugs work perfect but red plug won't. Adapter has 3 rows of connections but the end in my car only has 2. Result can't get rear speakers to work. Another adapter I can get?

dennis Apr 26, 2016

1 answer

If you purchased the product from Crutchfield, feel free to contact our Tech Support team. They can walk you through the connections 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/.

kenneth Apr 26, 2016 (Staff)

I have a 2005 audi allroad with bose system but does not have three plugs only two .will this wiring hardness work?

jesus Apr 20, 2016

1 answer

I think so. That's how my Bose system in my TT was.

james Apr 20, 2016

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Metra 70-1787 Receiver Wiring Harness For select 1994-07 Audi and Porsche vehicles

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Installation notes:

Additional items are required: