Oil Pressure Gauge Is DOA

[Sully]

The oil pressure gauge has been DOA since I bought the truck two and a half weeks ago. I thought it was a broken wire in the oil pressure wiring harness that was causing the problem, but after replacing the harness, the gauge is still dead. On the harness, there were three plugs (one black, one white, and one black with what appears to be a jumper) at one end (in addition to the oil pressure plug).
Does anyone know what these are for and what, if anything, they connect to? Mine had nothing attached to them and I could only find one thing in the engine remotely closeby that looked like it could take an electrical connection. Please forgive me since I don't know what all the engine parts are (I'm still getting to know my cruiser and still need to get the FSM) but I've posted two pics of the unknown object (located on the passenger side of the engine block).


Thanks for whatever light you can shed on my dilemna. Stay tuned for the next thread of "name that rubber... part."

 

[KliersLC]

Those are sending units, not for sure, but they probly need to be hooked up for your gage to work...
If you can, plug them in and I bet you get some sort of change
Dan

 

[cruiserdan]

The "can" is the oil pressure sender. Two wires connect ot it. The other wire goes to the A/C Compressor IIRC.

 

[Sully]

Do you know which plug goes to which pin?