Battery Amp Meter

ame2entre · April 3, 2022

I am installing a 2nd battery on my 2016 2500HD and just noticed I am missing an Amp Meter around the negative wiring. The harness is there, but the meter/plug is missing. I have no idea if this was removed by the previous owner or if it wasn't included during original purchase.

Does anybody have a part number for the amp meter, or an idea if I can add one?

AbzDad · April 5, 2022

The new harness for the second battery comes with the plug. The original connection into the main harness has a cap over it that you have to remove. It looks like that is what you are showing in the pic. This pic below shows both ends of the connection, new harness (right side) and existing harness (left).

ame2entre · April 5, 2022

Ok, I think I understand what i need. Thank you for the picture. In the videos and pictures online it shows it like a typical ampmeter which encompasses the negative wires, though the examples I've seen online are either different year Silverado, or have been a 1500.

I am thinking that for my model it is instead a 'plug and play' ampmeter through the harness rather than what i'm seeing as a circular enclosure that the negative wires feed through.

Follow up question....with this harness do I still need an Isolator and fuses to add a 2nd battery?

AbzDad · April 7, 2022

You need the isolator and the harness. You have to remove the old harness. The picture below is correct except you don't need #10, that plugs into your the existing plug pictured in the previous post. You do need #7, which is mounted to the firewall. #2 is screwed into the fuse box. You will need #4, as that is the ground cable for the second battery.

#7 is GM part number 12135194. The harness is 23279188. This fit my 2015 2500 and are the same for the 2016.

ame2entre · April 7, 2022

15 minutes ago, AbzDad said:

You need the isolator and the harness. You have to remove the old harness. The picture below is correct except you don't need #10, that plugs into your the existing plug pictured in the previous post. You do need #7, which is mounted to the firewall. #2 is screwed into the fuse box. You will need #4, as that is the ground cable for the second battery.

#7 is GM part number 12135194. The harness is 23279188. This fit my 2015 2500 and are the same for the 2016.

This is great info! Thank you

ame2entre · April 7, 2022

One more follow up question....Does the set-up you described--with the GMC relay and harness--completely negate any 3rd party Aux battery kits? Do i need to buy any additional fuses or an isolator? Or are those parts you listed all I would need?

AbzDad · April 13, 2022

I did not have to change any fuses, add anything beyond what was pictured or program anything. This is supposed to be the exact setup for the aux battery on a gas 2500.

The batteries should be the same, if possible.

I only use my second battery for a winch, running my subwoofer and occasionally to jump start a few cars. I have checked the voltage often, always at 12.9v after driving.

ame2entre · April 13, 2022

Gotcha... i have the 6.0L gas 2500hd as well. I am going to be running a front winch and occasionally a few other things. I'm waiting on the harness to arrive. Hopefully this simple set up gets me up and running. Thank you for your help on this!