2014-2019 GM/GMC Work/Custom/Elevation trim Vehicles with 4" or 7" Screen R2G

Built to order parts in stock!

Starting at :

$105 USD
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Pickup available at LLJ Customs Secret Lair

Usually ready in 2-4 days

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Adding a Sub to your new 2019 and up GM factory radio has never been so easy. Our GM T-Harness design truly works as advertised and doesn't need a laptop or overcomplicated steps. Our plug and play GM T-harnesses are guaranteed to deliver the signal you need for adding quality bass. The Gm T-harness and active processor options we pre-selected for you will over deliver, every time.

Want to target and modify a specific frequency for better results? Take a look at the LinkDQ. Maybe you have no bass or want to go past what the vehicle (or a flat signal) can deliver? the bassRESTOR will be the best tool for the job . The patented technology means, no turn-on pop when using the audio turn on feature. As well as no dead radio screen, given that we just use the audio and don't mess with the Canbus system. Other features like clip detection let you know when the signal you're using from your vehicle is starting to bottom out and introduce distortion. Some other benefits are: 

Harness is 18 inches in length and will come pre terminated and wired to the Unit selected.  
  • load resistance built in 
  • Audio Turn-On (prevents turn on/off pop)
  • High grade aluminum 
  • 300v oil/fire resistant wire
  • 5 year warranty 
  • Distortion detection 
  • 10v+ of signal output 
  • T-harness is 18-20 inches end to end
  • 12v remote turn on for amp 
  • 1000% plug and play 
  • Abrasion resistant loom
  • TESA Taped to fit OEM   


If you’d like to amplify your doors or add multiple amps to your Ford vehicle we offer our Elite Loopback Harness. This was designed to allow you to keep using the factory wiring, NO cutting, NO splicing. Add an amp quick and simple without ruining your vehicles wiring or voiding your warranty.

Vehicle Year Fitment Guide:

  • Volt 2014-2018 none bose
  • Silverado - WT, Custom or Elevation trim level 
  • Traverse (please check with support for correct connector)

LLJ Customs 1618GMWV 2014-2019 GMC CHEVY OEM amplifier T-harness 
  • 2019 (HD trucks) Supported models must verify radio is SILVER behind screen before purchasing.
  • Does not support Vehicles with  8" or 4" Screens (only for 7"screen Work vehicles LS ) ! Measure Screen from BOTTOM LEFT to TOP RIGHT corners)
  • TRUE Plug and play 
  • All soldered and shrink tubed connection, wrapped in tesa tape 
  • 15inch of amp remote turn on wire included when purchased with an LOC unit
  • Option to extend amp turn on wire an additional 15 feet. 
  • Cut and hassle free, simple and quick
  • Please verify this is the harness for your vehicle by looking at the harness behind the screen
    ** Harness will ships 2-5 business days after ordering ** 

    Shipping Information

    Our on-line store is open 24/7 and we ship Monday through Friday, excluding some holidays. Orders received for products without shipping restrictions on its product page will ship the next business day when received before 12:00 p.m. PST. Orders in high demand will have an estimated production time listed on its product page and will ship according to the date listed.

    Lead Times

    -In-Stock: product will ship in 2-5 Business days

    -Out of Stock: product is not available

    -Backordered: product can be ordered but can take 30-90 days. Factors can be: order demand and/or parts availability.

    How your signal is delivered Matters !

    Audiophile quality signal built with the highest quality materials at the best price! Zero to no resistance means les heat and a better signal.

    Best Active Line Output Converter (LOC) :

    The best Loc you can get is one that offers the features you NEED at a price that makes sence for what you get. Hands down the best LOC on the market is the Bassrestore from Wavtech! This magic box has everything an LOC should be with the fetures that matter.

    see what else we have ..

    Are you In Arizona?

    We would love to have you stop by our shop and answer any questions you may have on a product or your project! Schedule your visit below :

    What Is High Level or Low level?

    High level : AKA Speaker level is an amp that can handle an input voltage of 8-40v. This high output is common in factory amplified vehicles or where the
    max voltage of a head unit is more then 10v. This is normally identified by a pigtail connection point or via the RCA on the amplifier (must check user manual to verify.) Some amps have a switch for this. NOT all amps have this future.

    Low Level : is 0-8v of signal voltage. This is most commonly found inaftermarket head units. or other aftermarket units that use can-bus. Most passive LOC units output 0-5v so they are considered a low level and are normally RCA to RCA. Modern day ACTIVE LOC units can output 0-10v of signal.

    In conclusion an LOC works as an in line filter that lest you control the signal, its intercity and in some cases the playable frequency range.

    If your amp takes a high level and it is within the vehicles factory output range then you dont need an loc unit and can wire in and out of your amp
    directly. In some fords the signal can be flattened at the OB2 furthering the simplification of the installation.