I have found that there is only 1 wire going to it at the back, and that is the ignition live.
The other wires do not seem to be anywhere to be found behind the gauges.
Is the gauge a Celcius, or Fahrenheit gauge?
If it is a Celcius one then I have a spare vdo dipstick sensor I could use to wire it up.
If it's a Fahrenheit one I need to try and find where the wire from the sensor on the bottom of the engine is going to, but without a ramp that could be tricky.
This is the gauge I refer to




