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Metra 70-1858 Receiver Wiring Harness

Connect a new car stereo in select 1985-2005 General Motors-built vehicles

Item # 120701858

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...

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Item # 120701858

In stock

About the Metra 70-1858 Receiver Wiring Harness

Metra 70-1858 receiver wiring harness

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

Metra 70-1858 receiver wiring 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 saves installation time since you won't have to cut factory wires individually, and this also enables you to re-install the factory radio if needed. 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.


  • 12V constant power
  • 12V switched power
  • chassis ground
  • power antenna turn-on
  • dimmer
  • left front speaker +/-
  • right front speaker +/-
  • left rear speaker +/-
  • right rear speaker +/-

What's in the box:

MFR #70-1858

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More details on the Metra 70-1858 Receiver Wiring Harness

Stacey B.

Product Research


Wiring Harness: This wiring harness prevents 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 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 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 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 Power Antenna/Amp Turn-On
Orange Illumination
White Left Front Speaker +
White/Black Left Front Speaker -
Gray Right Front Speaker +
Gray/Black Right Front Speaker -
Green Left Rear Speaker +
Green/Black Left Rear Speaker -
Violet Right Rear Speaker +
Violet/Black Right Rear Speaker -

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Customer Q&A

6 questions already asked

My 1993 suburban has 6 speakers. 2 in the dash, 2 in rear doors, and 2 in rear cargo area. This harness looks to be for only 4 speakers. How do I power the two not included in the harness?
[ Larry  Jan 03, 2019 ]
3 answers
Hi Larry, you will have to splice 4 together. put the dash on the front channel and the back 4 on the other channel. keep the positive and negatives straight.
[ Bernard  Jan 03, 2019 ]
Car head units traditionally only have 4 speaker outputs in the wiring harness. Chevy has probably wired the 2 sets of rear speakers in parallel to share the amplifier power from the head unit. You can keep the wiring in that fashion or add an amplifier to provide additional power to the extra set of speakers.
[ Daniel  Jan 03, 2019 ]
Rca outputs to an amp powering the largest pair of speakers.....or if your head unit has enough rms, splice into one set of speaker outputs, be it "front" or "rear"
[ Joseph  Jan 03, 2019 ]
Is this the only harness I need? My radio has 2 harnesses coming out of it
[ Roger  Jul 09, 2017 ]
1 answer
This will depend largely on your vehicle. For details on 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 what you will need for an installation.
[ Kenny  Jul 11, 2017 ]  Staff
What gauge wires are these?
[ Brice  Mar 12, 2016 ]
3 answers
16 gauge
[ Bob  May 01, 2018 ]
20 to 22 ga
[ William  Mar 16, 2017 ]
I'd say about 18-20 gauge
[ Chadwin  Mar 12, 2016 ]
I have no sound is there a trick and I am trying to install a aftermarket amp and sub?
[ rick  Feb 06, 2014 ]
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. You can also post your question in our forums: Or try our online support center:
[ Krissy  Feb 06, 2014 ]  Staff
Will it work with the onstar option?
[ Perry  Dec 17, 2013 ]
1 answer
The ability to retain OnStar controls with aftermarket receivers will be determined by the receiver you are using and the vehicle you have. For full information on this type of integration (including the parts you will need) please contact an Advisor by phone or online chat.
[ Jeff  Dec 18, 2013 ]  Staff

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