Elite Harness system layout

2019-2024 GM | GMC | Buick | Cadillac - Aqua & Tan (with no Bose Amp) Base Connector

In stock

Key Features

  • The base connector is what connects to the factory audio source. EX: radio, factory amplifier)
  • Can be used as a T-harness or a Loopback harness
  • Abrasion resistant loom
  • Vehicle OEM connectors
  • Constant 12v +/-
  • Retains ALL Factory functions as they are
  • Designed, Tested and Hand-built by us.
  • 5 year warranty guaranteed

Starting at :

$70 USD
This product is only available through our Custom Elite Harness Builder Program. (CEHBP)
Email: Support@lljcustoms.com
Text or schedule a call: 602-320-7004



Our 2019-2024 GM/GMC A/T Elite Harness has been tested, redesigned and modified to what it is now by our team at LLJ Customs. The “Elite Series” harness has been years worth of time and effort to provide our customers with a product that will last a lifetime. This option is an all-in-on solution for the ultimate DIY’er. After years of developing our own wire and combining LOC’s, processors, DSP’s and companies like Audio Control and Rockford Fosgate, who offer amplifiers with a high level input signal. By combining these top shelf solutions for the 12V market you can get an entire system upgrade at the same price of a factory head unit upgrade alone.

The Elite T-Harness allows you to add an aftermarket mono amp/subwoofers while retaining all the features in your vehicle like the Bluetooth, Steering Wheel Controls and OnStar. This harness was designed for the Non-Bose, Non-Factory Amplified system. You are able to build and customize your harness to your preferences and needs; like the length of the harness or adding an LOC unit of your choice. We offer a variety of choices like an Audio Control LC2i Pro, a Link2 or LinkDQ from Wavtech for when you are just adding a subwoofer/s. With an LOC added to the harness you are getting a full plug and play set up; with the harness providing signal and the LOC unit providing RCA out and remote turn on to your amp.


Every unit ordered with the harness will come pre-wired and is tested before leaving our facility. Every product purchased from us comes with a 5 year warranty, including any processors, amps or DSP’s.

Silverado- 2019-2024 -ALL
Tahoe- 2019-2024
Suburban- 2019-2023
Traverse- 2018-2024
Colorado- 2018-2021
Impala- 2018-2019 none bose
Malibu- 2019-2022 none bose
Blazer -2019-2021 none bose

Sierra- 2019-2024 -All
Yukon- 2014-2023

*For the Non-Bose, Non-Factory Amplified system the connectors will be located behind the glove box, above the kick panel. This harness is for the Aqua and Tan connectors, please verify this is the connect you have. They are not interchangeable; ordering the wrong color may cause delays in your install by needing to exchange the harness.

*Harness includes remote turn on wire when purchased with an LOC/Processor only.
*This item has an $25 restocking fee, please verify the connector color is correct before placing your order*

Looking to add a sub? Keep the install simple with your 2019-2024 T-Harness:
  • The 2019-2024 T-Harness will plug in behind the glove box, above the kick panel.
- The connectors can be either Aqua and Tan or Black and Gray, remember to verify before placing an order.
- In small SUVs or Pick-Ups the connectors may be behind the screen (select 2018-2022 models)
  • The LOC that was ordered with your harness, or your own you attached, will provide RCA out and Remote turn on.
- Run your RCA wires from the output on the LOC to the RCA input on your mono amp.
- Run your remote turn on wire (blue wire) from the LOC unit to the mono amp.
  • Lastly run your power wire to your amp from the battery and a ground wire within 18 inches or shorter.
- The chimes are not affected in any way when adding subs.

All done! You’ve added a sub, congratulations!

Please verify the connector in the vehicle BEFORE placing an order. All Base Connectors that need to be returned, refunded or canceled due to the connector not being verified will have a Restocking Fee of $15. The connectors need to be in the exact same condition as they were sent in. Any damage or alterations made will void all exchanges and returns.

Elite T-harness Accessory Options-ETA

-Must Have a Base Connector to use this Accessory (BC)

The question is always what is the difference between the T-harness and the Loopback and the simple answer is, the T-harness is ideal for adding a Subwoofer only/mono amp or in a situation where you plan to run your own wires from the aftermarket amp to your new speakers. More information in the next page.

Elite LoopBack Accessory Options-ELA

-Must Have a Base Connector to use this Accessory

Our Loopback is simply the best option for any installation. Not just do you get the SIGNAL from the factory source unit but it also comes with 12v DC +/- to power your LOC or DSP. It also has a RETURN side that feeds from your aftermarket amps output, back to the factory speaker locations via the factory wires. The Loopback can also be tied together at the end, closing the loop in essence making a T-harness so you can start small and grow without needing to buy more.

Elite GX:500 S.I.K Options

Our S.I.K kits were the first of their kind to ever exists in the 12volt market. A solution long needed but never provided. "You need new speaker wire," was always the answer. That's no longer true. Increase the output and performance of your factory system in under 30 minutes. Our design places the aftermarket amplifier in the middle of your Elite Harness System.

Take the factory signal modify, tune, amplify and right back to the factory speaker locations. The amps we provide as a choice, we have used over the years and know they will work well in the particular function. Meaning all you have to do is plug in connect power and enjoy. Furthermore if you want to add an amplifier for subs we offer the option to add an Active LOC to your harness for future integration. Check out more below.

-Most Have a Base Connector to use this Accessory

Are you in Phoenix,Az?

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.

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