Sadly I don't have the workshop manual. nor do I have any wiring diagrams. The multimeter registers a connection to ground though. I think I have already concluded that the connection to the neutral circuit, or from the neutral circuit to the ECU must be the issue, but I can't find any info on Google about the ECU pinouts, or where the wires terminate so I can find where the issue lies. I have read about a diode in the circuit somewhere. Could this be the problem? If it could be, where is it? Thanks for the replies people. Hopefully we can help others that may have the same issue by solving this one.