Few Niggles I Can't Sort

[GT4 JDM]

Hi folks.

On the water outlet theres the temp gauge sender and i cnt get it to work i started fiddling around and found a wire that made it work, but it was meant for

the one along from it, does anyone know what it is ? I was told it was the a/c temp sensor or the cold start, it is hard to start when its cold though ?

There isnt anything on the loom for the temp gauge sender and im really stuck on what to do as it no longer works on where it was.

The speedo also doesn't work, though it is a jap import and had a converter on it, but now iv put in a british gearbox, the gauge sits at 25mph but goes and stays

at 0 when the ignition/ engine is on. Im guessing the british one may be different ? Cable/electronic ?

I did get the error code for the water temp sensor but it went away ? The only other code im getting is for the speed, vehicle speed sensor and/or circuit ?

Any help would be great and very much appreciated.

Thanks.