Mike1998XJ

I see a 1998 oil pressure sending unit has a plug with 2 wires.
A 1999 has a plug with 3 wires.
Anyone know what the third wire does?
Can a 1998 sending unit (2 wires) be used with a 1999 plug with 3 wires?
Thanks

Mike1998XJ

No one knows what the 3rd wire is for on the 1999 oil pressure sending unit? And why the 1998 sender has only 2 wires?

Thanks
Mike

Abovetimberline

i can tell you that the jeep dealership here says they are not interchangeable,because they have different part numbers,there service tech said the 3rd wire is a transducer,the way he exsplained it was the 2 wire guessed at what the pressure was,and the 3 wire knows what the pressure is. I guess that means it is more accurate. If your feed wire is 2 wire i would think it should be 3 to work.

Mike1998XJ

Thanks Mixed...
I can buy that... As soon as I switched to the 1998 computer with the 1999 (3) wire harness with the 99 sending unit my oil pressure only comes up to 20psi no matter what. When I run the 1999 computer it works as it should.
The only thing is the 1999 computer won't run many of the functions on the overhead console. Meaning the compass, average MPG and so on don't work. I need to figure out how to make that 1998 computer run the 1999 oil sensor since I used the 99 engine wiring harness (3 wire).
I do have a 1998 sensor so I suppose I could bolt that in and see if it will work with the 1999 (3) wire harness and the 1998 computer!
Always a challenge!
Thanks for your help.
Mike

Mike1998XJ

Ahhh! I went out to cut the 3 prong plug off to wire in the 1998 (2) wire plug but couldn't bear to do it. It would leave that transducer wire dangeling.
That will be a last resort...
I'm going to find another way to make this work correctly. Somehow...
Mike

Maybe if I call those Painless Wiring harness guys.

seanxj/tj

I’m dealing with similar issues, what’d you end up doing?

lawsoncl

Probably bought the correct sensor.