I don't know if this helps but there's a wiring schematic on P28.
http://www.espar.com/tech_manuals/Hydro ... 3%20JE.pdf
I hope you've already solved the problem - the diagram shows the cabling for socket, plug and unit - so it should be possible to work things out.
There are + and - connections a + take off for the dosing pump and 3 other connectors on mine - diagnostics, alternator and switching - the latter being the one that the manufacturer wants you to only connect to their exceptionally expensive and minimalist thermostat / timer /programmer equipment.
Regards,
Bryan
p.s. The manufacturers website also gives marine installation instructions in PDF