MM,

I have shorted this now and still not working - so i guess this indicates a problem elsewhere - presumably a short or break in the wire.

I guess i just have to trace both these wires back to the headbox and do a continuity across each joiner.....

Could be the connector onto the MPU bpard in the backbox is the problem, could also indicate a deeper problem such as a switch matrix issue.  Is this the only switch on the playfield not operating?  If it is then most likley a connector problem.

If you need a micro switch RTBB whom sponser the sight have many (see their web site) fast delivery too.