H104L Voltage boost harness for 1996-2004 GM trucks with 1 volt increase for Lithium batteries


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1.00 LBS
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This voltage boost harness fits 1996-2004 GM Trucks and SUV's with oval GM alternator plug. The longer blue wire gets connected to an ignition switched 12V+ source to turn the alternator on and off with ignition. This harness can be used with stock alternator harnesses on 1996-2004 GM trucks with oval 4 pin alternator plug, and can also be modified and hardwired to ignition 12V+ for engine swap applications where the stock alternator harness is not available. NOTE: This unit is NOT FOR USE ON STANDARD 12V AGM BATTERIES. This module will increase the charging voltage by 1.0 Volt, and will swell and damage AGM batteries. Please check with your Lithium battery manufacturer to verify the proper charging voltage before installing this module!

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  • 5
    Voltage boost

    Patrick | 3rd Mar 2023

    Definitely a must if you have a lithium bank. Mechman for the win!!!!

  • 5
    H104L Harness

    Joshua Davidson | 29th Nov 2022

    This harness does exactly what the description states the item will do. Was wanting to go from 14.8v to 16v in my car audio bass vehicle. Called Mechman and spoke to a representative about adding a voltage regulator to my Mechman elite 400 amp alternator. He asked me a few questions, then advised me, it'd be cheaper, easier, and less hassle, to simply go with this harness. I purchased harness, wired it up, and BINGO, voltage right where I wanted it. Couldn't be more happy. Thanks Mechman.

  • 5
    Voltage boost harness

    Jason Miller | 4th Aug 2021

    Love it. It works great I give it 5 STARS

  • 5

    Joseph lyles | 7th Jul 2021

    15.5 after installing it from 14.7. I charge my lithium before hand so my alt won’t be struggling to charge my lithium bank. Alt is happy and so is my amp and lithium

    ***Thank you for charging the lithium batteries BEFORE installing and forcing the alternator to charge them. THAT IS THE CORRECT WAY TO DO IT!! [email protected] ***

  • 5
    Great Product

    BassnBusa | 4th Jun 2021

    Immediately after installation alts charging at 15.3 from 14.9. After resting a few hours charging is at 15.5-15.6

  • 5
    Works great simply install, great help from MechMan support

    Garry | 1st Feb 2021

    Would buy again but would defeat the purpose because I only need the one! :)

  • 5
    Alternator plug

    SHAWN MARKER | 29th Oct 2020

    Works like a charm...hands down best alternators I've ever used!!