Rally dash oil pressure gauge issue.

Dartswinger70 said
How sensitive is the system to resistance? I feel like the sender is good when checked with an ohm meter, and the wiring from the sender to the pc board is good. Could it be the printed circuit board? Would the guage peg high when the sender wire is grounded button respond otherwise if the pc board is bad? A short to ground is no resistance or ohms at all.

I think you need to test the gauge's response to at least two more resistances.
The test you did here suggests the gage and connecting circuit are working correctly, but the sending unit is not.

Dartswinger70 said
I did an ohms test with engine running and it is 70 ohms and gauge reads low. I hooked up a snap on oil pressure gauge and I have 45 psi at idle. i am going to try a sender before going after the gauge. I seem to think or read that 70 ohms will real as "low" so I am thinking the sender is not working correctly.

Why do I say that?
Ask yourself at 45 psi what should the sender resistance be?