Asalamoalaikum All. I am in the process of writing up a guide for this speedometer's installation and will post a thread for it in a day or two. But for now to make it short and simple this is what I did:
The issue being faced was that the speedo would not switch off even when the key was out and car was locked. I've had a Reborn too and randomly thought of how its speedo behaved when I locked or unlocked the car or when I put the key in ignition. Those who've had 8th Generation Civics would perhaps understand what I refer to. It occurred to me then and it got me thinking whether this speedometer is meant to behave the same way. I studied the circuits with the help of a very dear friend who also happens to be a really good electrical engineer. We did a couple of trials which gave us hope and led us to finally work on a resolution. This is what we did: We intercepted the direct current connection from the speedo's grip, attached a relay and connected it with the car's central locking system. The result was that the speedo would activate when we would unlock the car and deactivate as soon as it was locked. No warning lights or sounds. There's another connection from the steering column to the speedometer which needs to be disengaged to facilitate this - once you open the steering column, there are about three different connections/grips. The smallest / tiniest grip is for the ignition dial to remain on when the car's started (the orange ring) - we observed that if this was left connected the cabin light would remain on when on 'Door' even when all doors were closed and the car was running. Disconnecting the grip normalised all behaviours.
The end result:
The speedometer works like a charm as it should do. Car locking/unlocking is working as it should. All interior cabin lights work as they should. The ignition dial glows orange when the car's unlocked but switches off when the car's started. This is the ONLY drawback - which really isn't a drawback to be honest. You only need the glow when the car's switched off. Who looks at the ignition dial when the car's running?
This simple solution has costed me a lot of time, effort and dough! Haha. Hope this helps you all. I have another speedometer which I will be using when attempting to write up a 'How To' guide. I will endeavour to have it up here as soon as possible.