Hi there,
Firstly, is it a Renault or Twin Cam engine ? If it's a TC, then the gauge sender is in the engine bay, an electrical sender plugged into the head IIRC. If you have the TC then I can photograph mine tomorrow morning and post up.
The cooling fan is an odd one because it doesn't look standard. The sensor plugged into the top hose looks very much like the aftermarket Kenlow ones which were popular here in the 70s/80s (and probably still are for all I know). Anyway, I have the same sort of arrangement on the Elan which has a sensor in the top hose going to a sort of control box thing which has a rotary dial from where you can set the temperature at which the fan cuts in at. There's also an override switch in the circuit to bypass the sensor if you want to.
If that is the case, then I have the instructions for mine and they are probably similar. I've posted the general arrangement & wiring, I can do the full 4 pages if this is what you have there.
Brian