I have the same gauge as what is in the pic that Julies sent and didn't use any redusers except for the one that is on the right of the pic. Like I said everything works except for the oil sending pressure switch. That is why I thought it might be the sending unit it's self that is bad. There is oil in the sending unit when I take it off and turn the hole down it drips oil out so I know oil is getting to it but know register on the gauge. Are you saying that I have to put another voltage drop on the gauge it's self to make it work. The wire off the sending unit test out to be 6 volt already. Any more ideas that might work?