Blazer Forum - Chevy Blazer Forums - [HOW TO] Big three upgrade

Background
The "big three" upgrade replaces your three main power/ground wires with heavier gauge wire.
These wires are:

1. Battery positive to alternator (charging wire)
2. Battery negative to frame
3. Engine block to ground

THE WHY
As we upgrade the electronics in our trucks, we demand more from our electrical system. The foundation of our electrical system is only designed to handle so much and as we expand on top of it, we need to reinforce the foundation so it can support the added weight- so to speak.

We need larger cable to allow a higher flow of electricity, with less resistance.

If you're running e-fans, a sound system, LED fog lights, a winch, power inverter, or any number of other things- this is a worthwhile upgrade for you.

If you're going to run a higher output alternator than stock- this is a NECCESARY upgrade for you

THE HOW
First let me start by saying this guide is for 98+ blazers, but could easily be adapted for any other year. There are a few ways this could be done, but this is the way I chose to do it...so here it is, the big three(4?) The Chevyriders way.

What you will need:
-5ft of 2awg black battery cable
-2ft of 2awg red battery cable
NOTE: 0awg could also be used as opposed to 2awg
-6 2awg eyelet style battery cable terminals
-1ft of 4awg black battery cable
- 2 4awg eyelet style battery cable terminals
- extended side post terminals(I was able to use 3/8 bolts instead. Your call)
-solder
-flux
-torch
-shrink tube(I reccomend thick walled made for battery cable-though that is not what's pictured)
-Large crimpers for cable terminals(I used a bench vice instead)
-wire brush
-dielectric grease
- basic hand tools to disassemble/reassemble

Step 1: Charging wire

-Unhook battery, and remove.

- remove battery tray(2 13mm bolts)

- remove wires from mega fuse block (13mm)

- remove factory charging wire from back of alternator(13mm)

-carefully cut away any tape holding the charging wire to the other 2 main power wires.

-follow the charging cable back to the terminal end you removed from the mega fuse block.

-use a pair of dikes to clip the charging wire as close to the terminal as possible(leaving the other power wire still attached to the terminal)
https://cimg2.ibsrv.net/gimg/blazerf...8b14f0c177.jpg

- shrink tube the terminal
https://cimg0.ibsrv.net/gimg/blazerf...af18486492.jpg

- measure your new RED cable to the length you need it, and cut it. I planned to hook mine directly to the battery +, but you can also connect it back to the mega fuse block if you prefer, so the battery cable length will depend based upon that.

- trim back the insulation on both ends- leave enough exposed wire to retain a gap between the insulation and terminal you are putting on.

NOTE: the pictures are of a black wire, but you want to be using your red wire for this section. This is just an example, as I won't be going over how to make the cables again in the next section

- dip the tip of the exposed wire in flux
https://cimg7.ibsrv.net/gimg/blazerf...d398456cae.jpg

- put the first terminal on the cable, and crimp it so it is secure.
https://cimg8.ibsrv.net/gimg/blazerf...f9536d84b6.jpg

- hang the wire so the terminal is down.

- using a torch, heat the terminal, and flow your solder into the terminal once it's hot enough. You pretty much want to keep flowing it in until it fills up. Heat at the end of the terminal to avoid burning your insulation.

- match up the cable how it's going to be on the truck, and figure out which way you want to "clock" the other terminal so it will match up with the surface it will be installed on. Getting this right the first time will save you a big headache later on.

- flux, crimp, and solder your properly clocked terminal on the cable.

-wire brush your terminals to clean them up

- slide some heatshrink over the ends and shrink it up
https://cimg3.ibsrv.net/gimg/blazerf...cfb537933e.jpg

Part one done!

Step 2: Ground wires

- remove the main ground cable from the engine block, framerail, and body(I had mine on the inside of the fender, but I believe they may have been on the radiator support from the factory?)

- measure your BLACK cable to go from your battery negative to your framerail

- cut, and create your ground cable following the same procedure as before.

Next is the engine block to ground. I chose to go directly from the battery negative to the block, although you could go from framerail to the block if you prefer.

- measure cut and create your engine ground with black cable following the same procedure.

Now there is the matter of that little ground from the battery negative to the body that was on the factory harness. I decided I would make one of those as well so I could 86 the whole factory harness. I used black 4awg cable for that one.

Now you have all your wires ready to go back in!
https://cimg2.ibsrv.net/gimg/blazerf...b248b6bfb8.jpg

Step 3: assembly

This part is pretty straight forward so i wont do a step by step, but rather just give some notes.

Clean all of your terminals and connections using a wire brush, and/or sandpaper before hooking them up. I would also do this for the other wires on the mega fuse block for peace of mind.

DIELECTRIC GREASE! use it liberally on all connections to protect them from the elements and corrosion.

Once you have it all back together, fire that blazer up and take it out for a rip! Have fun with it!

https://cimg2.ibsrv.net/gimg/blazerf...6f19bab3ce.jpg