Several years ago I purchased a Vanguard V-Twin, horizontal shaft engine and it's been in storage ever since. I did start and run it a couple of times a year. I am now going to put it into service. I had to install the wiring harness, but the book that came with it was one of those don't do this books. No help at all. Hooked up the harness and every thing works fine, but there was no wire for the oil pressure switch. There is one extra wire
( White ) with a round Female push on connector, but to short to reach switch, which has a male spade connector. I purchased a Vanguard repair manual, but it didn't show the wiring for the oil pressure switch. Weird huh!
Please Help. Thanks JC

You have the harness for the vertical shaft motor not the one for the horizontal shaft

Ground the wire out and see if your light or gage does something which ever you have,
If so just make a jumper wire.
Luck