Have a 2003 M/C 5.0l,Searay 300 sundancer, Temp gauge not responding, replaced thermostat, switched temp sensor from other engine to not working still nothing. The gauge is in a cluster with one gauge working /reading, oil, volts,trim position. When I turn the engine seitch on the gauge moves ever so slightly. Checked in the back of gauge , everthing seems tight and no rust. Any suggestions would be great.