Steve Ark

He ripped out the EFI and went naturally aspirated. In doing so, he cut all wires to the oil pressure sensor. I would like to restore this system because I like the idea of 'no oil pressure, no fuel pump'.
However, the new Standard auto parts PS-256 pressure switch has no terminal legend on the unit or the box. Does anyone know which tab is for what? The center terminal is silver (power in?) while the other two are dark in color. But, which of the dark ones is the 'normally closed'? SAP has been no help with the comment...."We generally keep minimal schematics for direct fit OE replacement parts. We usually only keep full schematics for our universal parts." Maybe one of the dark tabs goes to the fuel pump relay while the other goes to the warning light?

General circuit

89onlyZ51

Are you sure you have the right switch? On your schematic, there are only 2 terminals, and electricity doesn't care which easy it flows thorough a switch - wires can be hooked up either way.

WVZR-1

If this car is an '84 NOT ALL were the same. Early cars used a 3 terminal similar to what you bought but later used a pair, (1) switch and (1) sender for gauge.

1st question - is the car actually an '84?

Where did your image come from in your post? Do you actually have an '84 FSM?

If you have an actual 1 terminal sender now for oil pressure BUY a PS-135 2 terminal switch that should be sufficient.

If you have a 3 wire like you purchased what are your wire colors at the switch you have to work with?

Much depends on what the PO actually did in the 're-wire'. How did the PO do the fuel pump relay?

'Butcher' might be a poor word choice! PO did as he/she desired. It's now 'your turn'.

A 3 terminal switch/sender the 'center' is generally thought to be gauge/pressure. An '84 is I believe that way. FSM should confirm.