I'm confused.

Yesterday, my dash oil pressure gauge dropped to the lowest position of the normal range, and just kinda stayed there, regardless of RPM.

As I don't have a mechanical gauge just this second to test true pressure, I thought I would do a couple simple tests to try to eliminate whatever I could. I read doing a Google search, that I could test the sender and gauge by pulling the sender wire.

According to the articles I read:

Key on, engine off: Gauge should read "0"
Key on, engine off: Pull wire off of sender, gauge should peg to high.
Key on, engine off: Ground sender wire and gauge should come back to "0"

But mine does the opposite. My gauge shows "0" UNTIL I ground the sender wire with key on. Then it goes full over!

Am I missing something? I'm assuming my gauge might be just fine. I'm hoping it's a sender. I can't afford replacing a pump just now.

Any ideas?