Elite Harness system layout

Base Connector | Accessory | Audio converter High to low (ALOC)

2019-2023 GM | GMC | Buick | Cadillac - Black & Gray (Without 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 with a T-harness or a Loopback harness accessory
  • Abrasion resistant loom
  • 100% OFC copper
  • Vehicle OEM connectors
  • Constant 12v +/-
  • Retains ALL Factory functions as they are
  • Designed, Tested and Hand-built by us.
  • 5 year warranty guaranteed

Price :

$65 USD
You must agree with the terms and conditions of sales to check out.
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 2019-2022 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.

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- 2019-2022 -ALL
  • Tahoe- 2019-2022
  • Suburban- 2019-2022
  • Traverse- 2018-2022
  • Colorado- 2018-2021
  • Impala- 2018-2019 none bose
  • Malibu- 2019-2022 none bose
  • Blazer -2019-2021 none bose

  • Sierra- 2019-2022 -All
  • Yukon- 2014-2021

*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 Black and Gray connector, please verify this is what the vehicle has. They are not interchangeable; ordering the wrong color may cause delays in your install by needing to exchange the harness.

*Harnesses ordered with no LOC unit will not come with remote turn on.

*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 2019-2022 T-Harness:
  • The 2019-2023 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!

** 2ch/4ch T-Harnesses  with no units currently have a 12-15 business day lead time, T-Harnesses with a unit currently have a 20-25 business day lead time. **

 **Loopback Harness currently have a 30-35 business day lead time, this timeframe can vary depending on customizations . **

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.

BC Fitment and Installation Notes

Vehicle Fitment


  • CADILLAC | 2019-2022 | ATS | Without Bose, AKG
  • CADILLAC | 2019-2023 | CT6V | Without Bose, AKG
  • CADILLAC | 2018-202 | XTS | Without Bose, AKG
  • CADILLAC | 2019-2024 | XT5 | Without Bose, AKG
  • CADILLAC | 2019-2024 | XT4 | Without Bose, AKG
  • CADILLAC | 2020-2022 | CT5V | Without Bose, AKG
  • CADILLAC | 2019-2014 | CT5 | Without Bose, AKG
  • CADILLAC | 2019-2024 | CT4V | Without Bose, AKG
  • CADILLAC | 2019-2014 | CT4 |Without Bose, AKG
  • CADILLAC | 2024 | LYRIQ | Without Bose, AKG
  • CADILLAC | 2019-2024 | ESCALADE | Without Bose, AKG



  • CHEVROLET | 2019-2024 | CAMARO | Without Bose
  • CHEVROLET | 2019-2024 | COLORADO | Without Bose
  • CHEVROLET | 2019-2024 | CORVETTE | Without Bose
  • CHEVROLET | 2019-2024 | CRUZE | Without Bose
  • CHEVROLET | 2018-2023 | EQUINOX | Without Bose
  • CHEVROLET | 2023-2024 | EQUINOX EV | Without Bose
  • CHEVROLET | 2018-2024 | TRAILBLAZER | Without Bose
  • CHEVROLET | 2019-2020 | IMPALA | Without Bose
  • CHEVROLET | 2018-2022 | BLAZER | Without Bose
  • CHEVROLET | 2023-2024 | BLAZER EV| Without Bose
  • CHEVROLET | 2019-2023 | MALIBU | Without Bose
  • CHEVROLET | 2019-2024 | SILVERADO | Without Bose
  • CHEVROLET | 2018-2021 | CAPTIVA | Without Bose
  • CHEVROLET | 2019-2024 | SILVERADO HD | Without Bose
  • CHEVROLET | 2019-2024 | SUBURBAN | Without Bose
  • CHEVROLET | 2019-2024 | TAHOE | Without Bose
  • CHEVROLET | 2018-2024 | TRAVERSE | Without Bose
  • CHEVROLET | 2019-2023 | VOLT | Without Bose



  • GMC | 2018-2024 | ACADIA | Without Bose
  • GMC | 2019-2022 | CANYON | Without Bose
  • GMC | 2019-2024 | SIERRA | Without Bose
  • GMC | 2019-2024 | SIERRA HD | Without Bose
  • GMC | 2018-2024 | TERRAIN | Without Bose
  • GMC | 2019-2024 | YUKON | Without Bose
  • GMC | 2019-2024 | YUKON XL | Without Bose



  • BUICK | 2019-2024 | ENCLAVE | Without Bose or factory
  • BUICK | 2019-2022 | ENCORE | Without Bose or factory amplifier
  • BUICK | 2020-2024 | ENCORE GX | Without Bose or factory
  • BUICK | 2018-2024 | REGAL SPORTBACK | Without Bose or factory
  • BUICK | 2018-2024 | REGAL TOURX | Without Bose or factory
  • BUICK | 2019-2024 | ENVISION | Without Bose or factory
  • BUICK | 2019-2024 | ENVISTA | Without Bose or
    factory amplifier
BC connection location

At factory HMI



2018-2019 Colorado, Canyon can be behind radio screen

All others the HMI is behind the glovebox, access is from underneath.

Installation/Tuning & Notes

LLJ Elite System Installation Manual

Color Code Card & Bass Roll-off info


  • You MUST verify connector Colors before purchase some will have the Black/gray and some will be Aqua/Tan. Vehicles with none Bose amp may still have a factory amplifier. Please reach out if you have any questions.  
  • Some vehicles have ANC without the Bose (Crossovers mostly) this is a 3 harness silver box normally under the center console. -ANC bypass GMBB2
  • Harness ordered with an LOC/Processor includes a remote turn on cable. 
  • Chimes will not be affected.

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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