Can't find wire to oil pressure sending unit

[Bamasand]

1998 Ford Explorer.The oil pressure gauge is constantly jumping.I purchased a new oil pressure sending unit and removed the drivers front tire to replace.There is not a wire connected to the sending unit.I have searched everywhere and cant find the wire.Could anyone please tell me where the wire comes from so I could trace it back.How could the oil pressure guage even move without a wire connected to the sending unit?Any help would be greatly appreciated!!

 

[1998Exp]

The sender is a switch which grounds the line when the pressure reaches some preset minimum (around 3 PSI, if memory serves). If the gauge is moving and the wire is not connected to the sender, it's probably touching the engine and intermittently grounding.

You did not say what engine you have. I am only familiar with the 5.0L. On this one the wire splits off the harness at the front of the engine, just above the water pump.

 

[Bamasand]

Thanks for your response.I will check again and see if I can find the wire.The engine is 4.o SOHC

 

[SoNic67]

I guess the wire broke off and now is making temporarly contact to some part of your car (any metal)...

 

[2000StreetRod]

Oil pressure gauge

Oil pressure gauge