And here it is, proven to work now.    Wells #PS-122   http://www.wellsve.com/showall_ds_oil.php   that NLA Toro oil pressure switch for the Onan engine? Or the Onan part that’s $159.00? Scratch that. This piece here ^^^ I bought at my local O’Riellys for $5.73.    Yes, it’s a three terminal switch, not two like the factor, but... it works. Terminals 1 and 3 are tied together and work when oil pressure is applied. They disconnect when there is no pressure.