I would start the engine, open the hood and watch the engine and fan. Also, keep
checking the gauge. If the gauge is rising over half way, the fan should spin and cool it and
switch off again. We know the new switch is good. A bad fuse, relay, low water level or
burnt out motor may also prevent fan from running. If the fan is spinning, that's not the
problem. Are you losing water/coolant? When it's running, do the hoses swell up and look
like they're going to explode? If so, you probably have a blown head gasket...that will
cause it to lose water and overheat. The water pump could also be at fault. I hope this
helps you. I'm interested to know what happens. Good luck