At idle the needle is all the way to the left. When it should go up even the slightest bit, it goes straight to 75psi and stays there no matter what the engine speed is.

I have the same ground and power with my water temp gauge and it works fine. This makes me wonder about the oil pressure sensor. I bought it used from a friend so it may have been dropped or who knows what since he last used it.

Is there anyway to test the sensor to tell if its bad or not? If I need to consider it being something else, please say so. Thanks