Special thanks to Icemark (www.mazdamark.com) for these instructions, which I copied and pasted here for others’ use. Please note that I am not the author.

It actually pretty simple. It’s just a matter of un-pinning and re-pinning the plugs. Take the FB01 (S4) cluster harness and cut the tape at the Y of the harness (you will need a little extra room as the plugs are further apart on the S5 cluster. Now looking down the female pin side of the plugs, there are little plastic tabs that hold the pins in. You will need to push those pins towards the middle of the plug to release the pin. I use a small pick myself.

Non turbo, Turbo will be slightly different because of the boost wires.

So, looking at the white plug,

Pin A = green/red

Pin B = blank

Pin C = Blue

Pin D = Black

Pin E = Red/green

Pin F = black/white

Pin G = Grn/white

Pin H = Blank

Pin I = Brwn/white

Pin J = Brown

Pin K = Yel/Blk

Pin L = Blk/Yellow

Black Plug:

Pin A = Black

Pin B = small Red/White

Pin C = Yellow/Red

Pin D = Blank

Pin E = Blank

Pin F = Yellow/White

Pin G = Blank

Pin H = Blank

Pin I = Yellow/Blue

Pin J = Grn/Black

Pin K = Large Red/White

Pin L = Tan/green