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Metra 70-1787 Receiver Wiring Harness

For select 1994-07 Audi and Porsche vehicles

Item # 120701787

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

Find what Fits your car

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

California customers:
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Item # 120701787

In stock
$19.99

About the Metra 70-1787 Receiver Wiring Harness

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

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.

READ LESS

What's in the box:

  • Receiver wiring harness
  • OEM Amplifier harness
  • 40" Separate red wire
  • Fuse tap
MFR #70-1787C

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More details on the Metra 70-1787 Receiver Wiring Harness

Stacey B.

Product Research

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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Customer Q&A

4 questions already asked

Q
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
A
The rca pig tails are for the speakers. I cut them off and wire it directly to the factory amp.
[ JESUS  Jan 30, 2019 ]
A
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 ]
A
I couldn't honestly answer this...I took it to an installer.
[ Doug  Jan 30, 2019 ]
A
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.
[ Krissy  Jan 30, 2019 ]  Staff
Q
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
A
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.
[ Krissy  Aug 10, 2018 ]  Staff
Q
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
A
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/.
[ Kenny  Apr 26, 2016 ]  Staff

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