I decided to try getting my oil pressure gauge going. I'm looking at the sending unit, and I see a 3 prong connector. I can't find the matching connector or wiring that might go to it. There is one to to top. I get nothing at the gauge, no movement at all.
Look at my picture. The sender is the one on the left. There should be only one wire attached. For my year it is purple. On the right side is another sender dependent on oil pressure. For me it was an aftermarket electric fuel pump that will shut off the pump when the engine is stopped even though the ignition is still on. (Like for example if I ran into a tree or something.)
You have something similar but it's from the factory. Your Jeep is newer than mine. It maybe was a hookup for a computer or something emissions related, I don't know. But for the oil pressure gauge, you want to hook up to the sensor that looks like mine.
I'd rather be lost on the trails than found at home!
That's a pressure switch, used for idiot lights, manifold heaters among other things. Three terminals, likely common, normally open and normally closed. Your pressure sensor is the round can right above the switch behind that bundle of wires. I think the sensor just uses a wiper arm across a resistive element. You can try using an ohmmeter from the terminal to a good ground and see if it changes with pressure changes. Or just say the hell with it and plumb in a mechanical gauge.
1986 CJ7, 4.2 w/4.0 head, TFI-HEI hybrid ignition, Clifford manifold w/Holley 390 w/cold air intake, OBA, 4.5" lift, Woody CV shaft and Tattons in front, 4.10 gears - lunchbox in front, Truetrac in the back, twin-sticked, blower upgrade for running topless, trying to keep it simple.
It's just a Jeep, and if you don't wheel it once in a while, it's not even that.
The three prong plug is for the Electric Choke Switch, but don't recall it being 3 prong as it is a more common 2 prong switch. It allows voltage to be applied for the coil of the Manifold Heater and carburetor Electric Choke.
If you are worried about what your actual oil pressure is and find that the OEM gauge is not accurate or functioning properly, do yourself a favor and add a small liquid filled pressure gauge to the side of the engine block so you can know at a glance whether oil pressure is present and at what the current pressure is at.
I used a small liquid filled pressure gauge that I bought from McMaster-Carr.com and added a 1/8 NPT thread to the existing pipe union for the Oil Pressure Sending Unit and Choke Switch.
The gauge in the picture is not liquid filled as it was changed out shortly after taken the photo.