[thoughtful]

I am trying to remember this on top of my head so here it goes:

Get a toggle switch. Wire Pin 1 of the DB-15 cable to one pin on the toggle switch. Connect the other pin to 10 on the DB-15 connecter. This should work for pX_sw_aux1 (or aux2: not sure) . X is the port number. I would suggest use port 3 or 4, its on the other side of the OI and mostly easier to layout your OI.

With this all you have to do is

relayX_fwd=pX_sw_aux1;

So when the button is in on position the solenoid is active and in off its not. (this will work for a single solenoid)

you can put the code in user_routines.c under where other relays have values assigned. I dont remember the exact line number.

Any questions are welcomed