I have that same problem. Only when I idle my temp gauge goes up past halfway mark. but when I drive off it goes down right away. So I know it has to do something with getting air to radiator. My fan doesnt come on at all with ignition on only when my engine is shut off.

When the engine is shut off and my cooling fan comes on once I put my key in ign and put it on the on postion the cooling fan shuts off. Is that normal with fan shutting off when ign is on?

I still dont know why my fan doesnt come on with ign on? When I turn the air on they both work. so I know the fans work. I was thinking maybe it was a sensor or something. PLEASE HELP!!!!