Requirements:
• Skill Level: Basic mechanical and electrical understanding
• Time: 1/2 - 1 day
• Special Tools: Yes
Goal: Make use of the second factory battery tray and have the install look as factory as possible.
These are special crimpers used for "open barrel" terminals. You can search for "delphi crimpers" and find them. I forget where I got mine from, it's been a while, but you should expect to pay around $30.

The crimpers allow you to make this type of crimp, which is critical. If the crimp is not right, the terminals will not slide into the connector.

Instructions:
Step 1.
Start by installing the battery isolator.
Battery Isolator (GM P/N 12135194). GM calls this a "secondary auxiliary relay".

It goes on the firewall, up and left from the brake booster.

How you mount it is up to you. If your truck is like mine, then it doesn't have the needed studs from the factory. So I used M6 threaded inserts and flange bolts from ACE hardware.

Step 2.
Install the relay that controls the battery isolator. I acquired mine as kit that included the relay, connector, seals, terminals, TPA, and CPA from lsxtune.com
The mounting procedure is identical to that of the isolator. It is also placed on the firewall directly above the wire coming from the alternator.

Step 3.
Install the fuse holder intended for dual battery use. I purchased my holder (P/N 19116352) and cover (P/N 15881616) from gmpartseast. It is a direct swap with the single fuse holder.

With those items installed you have completed the install of the new hardware. Now it's time to tackle the wiring aspect. There are only 3 wires we need for this. Switched 12V (only hot when key is in ACC), constant 12V (always hot), and ground. Orange wire is used for switched 12V, red/wh is constant 12V, and black is ground. The two 12V wires will come from the fuse block and the ground will come from the passenger side head. The orange wire is technically the "ignition 3" circuit and is controlled by the BCM.
Step 4.
We need to add the connector that would be there if the truck originally came with the TP2 option. To get this started you need to remove the fuse block and expose the harness connectors underneath. The connector we need to tap is the middle one closest to the engine. Notice the single terminal in the upper right hand corner? That's the corner we will be adding to.

For this procedure your going to need two terminals (P/N 15304711) and GM specs 20 gauge wire for this. The factory colors are orange and red/white stripe. I found mine at eficonnection. You'll need to use those special crimpers at this point and make a red/wh and orange wire that looks like this. *there is a locating tab on the backside of this terminal that needs bent down in order to seat the connector*

Once you have that done, you need to remove the red TPA from the connector. When the terminals seat they won't be able to be removed without a special tool, the TPA is added insurance. I just used a small flat head screwdriver and it comes loose. Then insert the red/wh wire into A5 and orange wire into B4. Make sure to reinstall the TPA.



Then connect the ground. There is a factory grounding point on the passenger side head. In this pic I've already ran the ground and incorporated it into the factory wire loom.

At this point we have our wires from the fuse block and our ground. I also went as far as to replace my alternator wire with 1/0 and cleanup the wire loom. Here are some pics of that little process. I'll start from the fuse block and work towards the passenger side.





So now everything is cleaned up, with our three wires loose in the bottom left corner of the above pic. Now we're ready to add the connector for these wires. For this you're going to need TPA (P/N 12160826), Connector (P/N 12160825), 3 terminals (P/N 12045773), 3 seals (P/N 15324976), and one plug (P/N 12059168). And you end up with something like this. Route this harness along side the alternator wire and zip tie it to the alternator wire just below where the alternator wire is zip tied to the AC dryer. The pinout for this connector is Pin A=orange, Pin B=Ground, Pin C=Red/Wh, Pin D=plug


Technically at this point you could order the factory AC Delco Battery Cables for the TP2 option and plug and play. But those cable aren't cheap, I'm going bigger, and why buy when you can make your own cheaper.
Step 5.
At this point is when I would run the power and grounds for the second battery. You need to run power from the fuse holder (bus bar side) to the top post of the isolator and then run power from the bottom post of the isolator to the second battery. The battery is then grounded to the driver side head via a M10x1.5 bolt. I also ran a ground from the second battery to the frame.
Here you can see my two 1/0 grounds running from the battery (bottom of pic) to the head and to the frame. I had to drill and tap the frame. I also had to shorten up one of the bolts because it was bottoming out in the head.


• Skill Level: Basic mechanical and electrical understanding
• Time: 1/2 - 1 day
• Special Tools: Yes
Goal: Make use of the second factory battery tray and have the install look as factory as possible.
These are special crimpers used for "open barrel" terminals. You can search for "delphi crimpers" and find them. I forget where I got mine from, it's been a while, but you should expect to pay around $30.

The crimpers allow you to make this type of crimp, which is critical. If the crimp is not right, the terminals will not slide into the connector.

Instructions:
Step 1.
Start by installing the battery isolator.
Battery Isolator (GM P/N 12135194). GM calls this a "secondary auxiliary relay".

It goes on the firewall, up and left from the brake booster.

How you mount it is up to you. If your truck is like mine, then it doesn't have the needed studs from the factory. So I used M6 threaded inserts and flange bolts from ACE hardware.

Step 2.
Install the relay that controls the battery isolator. I acquired mine as kit that included the relay, connector, seals, terminals, TPA, and CPA from lsxtune.com
The mounting procedure is identical to that of the isolator. It is also placed on the firewall directly above the wire coming from the alternator.

Step 3.
Install the fuse holder intended for dual battery use. I purchased my holder (P/N 19116352) and cover (P/N 15881616) from gmpartseast. It is a direct swap with the single fuse holder.

With those items installed you have completed the install of the new hardware. Now it's time to tackle the wiring aspect. There are only 3 wires we need for this. Switched 12V (only hot when key is in ACC), constant 12V (always hot), and ground. Orange wire is used for switched 12V, red/wh is constant 12V, and black is ground. The two 12V wires will come from the fuse block and the ground will come from the passenger side head. The orange wire is technically the "ignition 3" circuit and is controlled by the BCM.
Step 4.
We need to add the connector that would be there if the truck originally came with the TP2 option. To get this started you need to remove the fuse block and expose the harness connectors underneath. The connector we need to tap is the middle one closest to the engine. Notice the single terminal in the upper right hand corner? That's the corner we will be adding to.

For this procedure your going to need two terminals (P/N 15304711) and GM specs 20 gauge wire for this. The factory colors are orange and red/white stripe. I found mine at eficonnection. You'll need to use those special crimpers at this point and make a red/wh and orange wire that looks like this. *there is a locating tab on the backside of this terminal that needs bent down in order to seat the connector*

Once you have that done, you need to remove the red TPA from the connector. When the terminals seat they won't be able to be removed without a special tool, the TPA is added insurance. I just used a small flat head screwdriver and it comes loose. Then insert the red/wh wire into A5 and orange wire into B4. Make sure to reinstall the TPA.



Then connect the ground. There is a factory grounding point on the passenger side head. In this pic I've already ran the ground and incorporated it into the factory wire loom.

At this point we have our wires from the fuse block and our ground. I also went as far as to replace my alternator wire with 1/0 and cleanup the wire loom. Here are some pics of that little process. I'll start from the fuse block and work towards the passenger side.





So now everything is cleaned up, with our three wires loose in the bottom left corner of the above pic. Now we're ready to add the connector for these wires. For this you're going to need TPA (P/N 12160826), Connector (P/N 12160825), 3 terminals (P/N 12045773), 3 seals (P/N 15324976), and one plug (P/N 12059168). And you end up with something like this. Route this harness along side the alternator wire and zip tie it to the alternator wire just below where the alternator wire is zip tied to the AC dryer. The pinout for this connector is Pin A=orange, Pin B=Ground, Pin C=Red/Wh, Pin D=plug


Technically at this point you could order the factory AC Delco Battery Cables for the TP2 option and plug and play. But those cable aren't cheap, I'm going bigger, and why buy when you can make your own cheaper.
Step 5.
At this point is when I would run the power and grounds for the second battery. You need to run power from the fuse holder (bus bar side) to the top post of the isolator and then run power from the bottom post of the isolator to the second battery. The battery is then grounded to the driver side head via a M10x1.5 bolt. I also ran a ground from the second battery to the frame.
Here you can see my two 1/0 grounds running from the battery (bottom of pic) to the head and to the frame. I had to drill and tap the frame. I also had to shorten up one of the bolts because it was bottoming out in the head.

