[SEL] OT - John Deere wiring diagram needed

[bill at antique-engines.com]

Sorry for yet another OT, but I know a lot of garden tractor folks are
also engine folks..and visa-versa, whatever.

I'm working on a John Deere 318 lawn tractor. The wiring is messed up - or
at least seems to be. The oil light stays on, even with the sender
DISCONNECTED.
It has oil pressure, the sender works, but the light won't go out so there
must be a problem in wiring.
I pulled it partially apart and see there are two wires at the oil light -
yellow and brown. Sitting next to the light socket is a black wire with a
spade terminal. Looks like it belongs somewhere, but have no idea where.
A wiring diagram would be very helpful, but I don't have any.
Can anyone point me to a source, or one online, or have a copy they could
email?

It's definitely a stationary engine until I get that working again.

Thanks,

Bill