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· Super Moderator
385 Posts
Discussion Starter · #1 · (Edited)
Just did a big 3 upgrade yesterday.
I used a kit from based on their #24472-Z. I called them and had them build that kit for me with 1 gauge to the alternator.

While the upgrade is simple, it wasn't easy--a real knuckle buster.
You'll want it up on ramps or at least the driver side up on a jack stand so you can get under to reach the starter.

extensions, wobble
1/4" driver is optimal for some tight-spaces
high-temp automotive zip ties
christmas-tree zip ties - in case you break or can't use the factory ones

1) disconnect and remove battery (negative first of course)
2) open the TIPM and unscrew and remove the positive lead going into it.
3) move TIPM out of the bracket and secure it out of the way above the master cylinder
4) remove TIPM bracket--2-3 screws (mine is missing one)
5) remove battery tray--3 screws, 2x 13mm up top, 1x 10mm down in the hole
6) unscrew remaining harness ends:
  • starter--from down below,
  • alternator
  • chassis ground just rear of the TIPM--there are two ground wires from the engine harness under the first nut, then the next nut is actually part of the stud--the whole stud comes out to get the final ground wire off. There is a christmas-tree plug holding this down to the fender. I was not able to get this one off the factory wire to move to the new wire, so used a new christmas tree plug for the new wire in the same place.
  • engine ground--this one is the real PITA--you can't see it. you have to follow it w/your hand, it's above/behind the oil filter on the block. if you follow the top of the little plastic oil spill-drain with your hand, it's just in front of that. It's a 15mm nut. If you drop the nut you'll spend a long time finding it... ask me how I know.
7) disconnect the clips
  • there is a plastic clip on the wire to the starter holding the second wire to the starter--just pull that second wire out of the clip
  • there is a clip holding the starter wire to the side of the block--get the clip open and the wire comes right out
  • there is a clip holding the harness to the corner of the valve cover--there's a weird barbed washer holding that down--you have to work it off--or break the washer, then the clip will pull off the stud
  • there is a christmas-tree plug holding the harness down to the fender under where the battery tray goes
8) you should be able to pull the original harness out now

Now I laid the new harness down next to the original and moved the clips over into the same places.
The clips are zip-tie style, you have to work a knife or fine screw driver under the barb to free the strap.
The new harness is much thicker with the loom and some of the clips had to go around the wire inside the loom--just sticking out through the loom.
I put all the clips onto the new wire going to the starter matched as closely in position as I could--measuring from the starter end. I put bends into the wire to approximate the original harness.

1) Install the wire to the engine ground first. This one is a royal PITA. You can't see it, and you can only reach one hand in there. You need a medium deep 15mm socket, a wobble, and a long extension to reach it to tighten it down. I had to ream out the connector to the engine ground a little to get it to fit on the post. I lost a lot of skin doing this one. It's a tight squeeze surrounded by some sharp things.
2) Install the starter wire next--run it down from the top, then go under and screw it onto the starter post. The kit includes a rubber cover end for this, but I didn't bother to use it. Stock didn't have one and it's hard enough getting in there with one hand as it is.
3) back up top attach the clip to the post on the corner of the valve cover.
4) the thicker wire won't fit in the clip holding it to the side of the block, but I ran it through that clip, closed it as much as it would and then used a zip tie to secure it there
5) get the other wire going to the starter back in the clip that holds the two together--this isn't easy with one hand
6) adjust and bend the wire so that you can get the christmas-tree plug back into the fender going below where the battery tray is.
7) now I used zip ties to make the wire from the engine ground follow the wire from the starter, similar to how the factory harness does (but factory harness they all share the same loom).

The hardest part is now done.

8) install the wire from the alternator, run it same as where the factory ran, next to the others, zip tie them together as necessary.
9) install the new ground to the frame behind the TIPM, reinstall the other two grounds on top of that stud's screw and then the screw on that--there is also a little plastic cap that goes on the end of the stud--replace that. Plug in the christmas-tree plug holding it down to the fender same as the factory wire had.
10) route the lines under where the battery tray goes, reinstall the tray, then the TIPM bracket, then reinstall the TIPM in the bracket.
11) install the new positive wire to the TIPM. I had to ream the hole out on the connector to be longer since the tab wasn't long enough. I also had to trim the plastic square on the lid that extends down over where that wire comes out of the box so that it would close--I just trimmed off a rectangle corner from it enough for the thicker wire to have room to exit the box with the lid closed.
12) reinstall the battery
13) now install the leads to the included military connectors--you'll have to man-handle the wires to get them to come in sideways so the connector will fit on the post--just do one side, then disconnect it while you do the other side. The kit comes with a regular nut on the military connector--you don't use that, you use the included nyloc nut to secure the wire ends.

Finally, connect and tighten the positive post, then connect and tighten the negative post.

Assuming you got it all correct it should all just work. Might want an extinguisher on hand just in case when you fire it up first.

· Registered
2010 Nitro SXT, 4.0 V6, 4X4
15 Posts
When doing the big 3 upgrade the starter wire is not part of the upgrade. The 3 connections are
1 - charging wire from alternator to battery positive
2 - battery ground to factory battery ground
3 - battery ground to engine block.
4 - engine block to body ground, this is optional and the reason its sometimes called the big 4 upgrade. Not all vehicles have a ground from the body to the engine so its often not done.
Also you don't remove any factory wires, you add the power and ground cables to them.
I did mine several years ago do to a "small" stereo upgrade lol. I ran 2 runs of 1/0 for each of the 3 upgrades as well as adding 4 batteries above the A/C charge location on the passenger side. I ran 2 more runs of 1/0 power from the extra battery bank to the rear along the passenger side and came up through the floor just before the rear tire. Both runs of wire were ran through PVC tubing that I attached to the bottom to keep it from getting damaged. The wire went into the cargo area and was connected to the amps I had under the floor. From the amps I ran 2 runs of 1/0 ground to a bolt i put into the floor underneath the rear seats. The amp ground was the hardest part to do because I had to have a wrench underneath as well as the ratchet inside to tighten the bolt.
I have pics of the installation on my Facebook page that shows the 4 Kinetik HC600 batteries and how I installed them if anyone wants to get some ideas for their own upgrades

· Super Moderator
385 Posts
Discussion Starter · #3 ·
Yes, leaving in the factory wiring is also an option, but full replacement is another. If you were to simply google search "big 3 upgrade" nearly every article mentions both options.

I prefer the cleaner result with fewer wires running--the new ones are big as it is already w/o having the factory loom also in there still.
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