3 Wire Oil Pressure Switch

Forgive my ignorance:

The oil pressure switch I ended up with has three spades, labeled NC NO and C. I know what these mean, but I have no clue how this is to be wired to my idiot light. Look who’s the idiot now.

Your enlightenment is appreciated.

 

Typically the wire to the oil pressure light (OPL) goes hot when you turn on the ignition, and the pressure switch supplies the ground. Normally the switch would have one terminal that's normally closed and grounded through the body of the switch. Switch on, no oil pressure, OPL is on. When the engine starts and the oil pressure comes up, the switch opens and the OPL goes out.

To use this switch, I expect you'll need to connect the NC contact to the OPL, and the C to ground.

 

I had a suspicion that the C would need to be grounded. I’ll break out the multimeter and see if it’ll ground through the case itself.

 

C is common between the NO and NC contacts ... but I suspect you knew that. I'm sure there's no ground through the switch body with this device.

 

You are correct. Well, what’s one more wire.... geesh.