Auxiliary Battery Wiring

Cable · November 15, 2017

My intention is to install an auxiliary battery for camping in a 20

17 Silverado 2500 using GM's parts.

GM's discussion of Removal/Installation procedure of Positive Auxiliary Battery cable, PN 23386298, on a gas truck with RPO K4B does not mention any connections that would energize the Auxiliary Battery Run Relay, item 10 in the attached drawing. The procedure only mentions connecting the cable to positive battery terminal on the under hood fuse block. The Auxiliary Battery Run relay is needed to energize the Auxiliary Battery relay, item 7 in the drawing.

In versions prior to 2014 this energizing voltage came from a connection made to B4 on the Under Hood Fuse Block.

Can anyone shed some light how this relay gets it's energizing voltage and where and how the connection is made?

Edited November 16, 2017 by Cable

jmassi · April 22, 2019

I'm looking to add this to my 2019 2500HD. Have you done this? do you by chance have a parts list? Also where did you find that diagram?

Gmman · April 22, 2019

I did this mod. There is a plug next to the battery that the harness plugs into. Its on the fire wall. It has a cap on it.

Gmman · April 22, 2019

1 minute ago, Gmman said:

I did this mod. There is a plug next to the battery that the harness plugs into. Its on the fire wall. It has a cap on it.

The main battery, Passenger side.

jmassi · April 25, 2019

Does anyone know what the GM part number is for the positive cable shown in the pic above?

Gmman · April 25, 2019

84276395

Brricha4 · September 7, 2019

Can anyone tell me if GM’s relay isolates and allows the auxiliary battery to operate in accessory mode or does it only isolate and operate the aux battery when everything is off? If so, does that only happen when the starter battery is drained a certain amount? The literature seems non-existent as to what the GM relay is actually doing. I’m trying to make this mod to operate the vehicles cigarette lighters and outlets to run camping equipment while the engine is off without depleting the starter battery. It’s not clear to me that this set up is actually doing that. Would appreciate any insight.

Whisper6691 · October 19, 2020

Okay I have installed the entire kit but still unable to locate that plug on the firewall has anyone taken a picture of the location? I have 2016 Silverado and All I need is to energize this relay

Chevyfan3 · January 18, 2021

I'm looking into adding the aux battery to my 2016, does any one know if the above listed harness also includes the isolation relay? Also does anyone have a part number for the negative harness? I have searched for info and this and most the threads I'm coming across are incomplete on the install. Thanks for the help!

bsp9493 · January 9, 2022

On 11/15/2017 at 3:32 AM, Cable said:

My intention is to install an auxiliary battery for camping in a 20

17 Silverado 2500 using GM's parts.

GM's discussion of Removal/Installation procedure of Positive Auxiliary Battery cable, PN 23386298, on a gas truck with RPO K4B does not mention any connections that would energize the Auxiliary Battery Run Relay, item 10 in the attached drawing. The procedure only mentions connecting the cable to positive battery terminal on the under hood fuse block. The Auxiliary Battery Run relay is needed to energize the Auxiliary Battery relay, item 7 in the drawing.

In versions prior to 2014 this energizing voltage came from a connection made to B4 on the Under Hood Fuse Block.

Can anyone shed some light how this relay gets it's energizing voltage and where and how the connection is made?

I am looking at doing the exact same thing with a 2016 Sierra 2500HD.

whenever I get close to finding the correct part number for the positive cable, the plug that energizes the relay is NOT the same:(.

I have included pictures of the plug from my vehicle for reference.

does ANYONE have a 2016 with this option factory installed? if so, can you please share the last 8 digits of your VIN so I can track down the correct factory harness.

OR

share the partnumber (the ones listed here and the ones I have been able to find do not match the plug in my vehicle.

Unfortunately, 3 dealers have been of little help:(

Thank in advance

d

AbzDad · February 7, 2022

Here is what I found. Part number for the harness is 23279188. Has the plugs that matches your picture.

eurobound · November 22, 2022

On 11/15/2017 at 3:32 AM, Cable said:

My intention is to install an auxiliary battery for camping in a 20

17 Silverado 2500 using GM's parts.

GM's discussion of Removal/Installation procedure of Positive Auxiliary Battery cable, PN 23386298, on a gas truck with RPO K4B does not mention any connections that would energize the Auxiliary Battery Run Relay, item 10 in the attached drawing. The procedure only mentions connecting the cable to positive battery terminal on the under hood fuse block. The Auxiliary Battery Run relay is needed to energize the Auxiliary Battery relay, item 7 in the drawing.

In versions prior to 2014 this energizing voltage came from a connection made to B4 on the Under Hood Fuse Block.

Can anyone shed some light how this relay gets it's energizing voltage and where and how the connection is made?

Can someone please tell me what exactly is the number 2 point of attachment? I have the factory harness already. I haven't had a good chance to look hard under the hood but was wondering if someone had a picture of the post this attaches to? Looks like its attaching to the fuse box on the back side? Any help would be much appreciated.

AbzDad · December 27, 2022

On 11/21/2022 at 9:39 PM, eurobound said:

Can someone please tell me what exactly is the number 2 point of attachment? I have the factory harness already. I haven't had a good chance to look hard under the hood but was wondering if someone had a picture of the post this attaches to? Looks like its attaching to the fuse box on the back side? Any help would be much appreciated.

It attaches to the back of the fuse box. There is only one connection there, if i remember correctly. You have to remove the old harness and replace it with the new one in the same place.

eurobound · December 28, 2022

13 hours ago, AbzDad said:

It attaches to the back of the fuse box. There is only one connection there, if i remember correctly. You have to remove the old harness and replace it with the new one in the same place.

Thanks. Yeah, I've had the harness sitting on my floor for quite a while and only after studying the harness and the pictures did I realize it replaces the original wire to the fuse box. Really appreciate you confirming that. I'm getting my batteries on Friday and will instal this weekend and will post some some pics.

BackRoadZ1 · February 11, 2025

On 11/15/2017 at 6:32 AM, Cable said:

My intention is to install an auxiliary battery for camping in a 20

17 Silverado 2500 using GM's parts.

GM's discussion of Removal/Installation procedure of Positive Auxiliary Battery cable, PN 23386298, on a gas truck with RPO K4B does not mention any connections that would energize the Auxiliary Battery Run Relay, item 10 in the attached drawing. The procedure only mentions connecting the cable to positive battery terminal on the under hood fuse block. The Auxiliary Battery Run relay is needed to energize the Auxiliary Battery relay, item 7 in the drawing.

In versions prior to 2014 this energizing voltage came from a connection made to B4 on the Under Hood Fuse Block.

Can anyone shed some light how this relay gets it's energizing voltage and where and how the connection is made?