My Greddy oil temp gauge suddenly peaked (to the peg) the other day. After I realized that it wasn't a real reading, I did some detective work. Even with the sensor harness unplugged from the back of the gauge, it still reads off the scale.

With power to the gauge, it sits rotated fully against the peg, which indicates about 200 Celsius. With no power to the gauge, it sits like this: http://i11.tinypic.com/313oac4.jpg (http://i11.tinypic.com/313oac4.jpg) It used to sit at the 30C mark when the car was off. The temp sender has a measurable resistance that changes with oil temperature, so it's likely not a sender problem.

A search revealed this thread with no resolution, along with a few others: http://forums.nasioc.com/forums/showthread.php?t=650561

Can you provide assistance/advice or point me in the right direction to get some help?

Thanks!