[wkooiman]

My temp switch goes to ground when the engine is hot.

I removed the wires a few months ago and when I reattached the temp switch, I slightly bent the contact so that it grounded to the intake. So, my fans ran whenever the key was on, hot or cold. It's an easy fix if that's your problem.

Granted, there are all kinds of temp switches, but most likely it works by providing a ground when the engine is hot.