Installed an A'pexi RSM entirely using the cluster harness.

[AKADriver]

I wanted to disable the speed limiter (for track days, of course), and I love retro crap, so I got a cheap early 2000s era A'pexi RSM with the blue lens from Yahoo Japan. The instructions tell you to tap into the engine harness, and you can do that, but for the RSM you can actually do a cleaner job tapping into the cluster harness.

The wires you need to tap into (with their designations on the factory wiring diagrams) are:

+IGN, MJ01, Green
Ground, MFE1, Black
Tach, MF01, Yellow/Red stripe
Speed Out, MJ04, Yellow/Green stripe

The speed limiter cut still works because the raw speed sensor signal goes into the speedometer before being translated somehow and then sent to the ECU. The Y/G wire from the speedometer is the other end of the Y/G wire that meets the ECU downstream.

Tips:

- There's a green with blue stripe wire that looks damn near identical to the green wire. It's the power for the illumination. You'll know if you got this one instead of the right green wire because it'll read ~3.0V!
- Connecting the speed signal wires: make sure the purple (input to the RSM) goes to the cluster side, and the pink (output to the ECU) goes to the body harness side.

This will work for both HUD and analog clusters, they carry all the same signals, just the cluster side connectors are different.

My finished harness. I don't know where I got this red tape from, it's not particularly sticky so it works well for rewrapping interior harnesses.



Everything done with crimps. I used the same type the RSM would've originally come with, and put bullet connectors on the speed signal so it's easily reversible. Of course the splice doesn't allow for heat shrink, so I used some 3M 1700. The factory actually did a similar thing on this harness with a splice in the ground wire. Cheap IWISS crimper worked fine for all this. You need three hands to get the mid-wire splices lined up.





There's a perfect amount of harness for the RSM to be placed in the console and obviously a lot of extra length if I wanted to put it on the column. I didn't get a pedestal with it, so for now it's going in the console below the radio.