cyberdyne digital

ok, I see what some of you are saying, that maybe when the fans come on, the voltage from the fans is affecting the reading on the temp gauge by affecting the voltage in the wire coming from the sender, right?

Well how would I check that?

idea, the power for the gauge is currently coming from a tapped fuse under the dash, I could wire it directly to the battery and see if that helps, or run the car with the gauge powered by a totally seperate battery to see what happens.