Temperature gauge reading hot while engine isn't on 2000 Cadillac Seville STS

I had this car since November of 2013 no issues, but now the temperature gauge is saying my car is running hot, so I naturally replaced thermostat, water pump, did a coolant and radiator flush, the engine isn't running as hot as the gauge says, but it keeps shutting my car off as the system says it's overheated. Help?

1 answer 1 comment
Have the engine coolant sensor tested, and the temp sender as well.
Thanks will let you know how it works, how do I locate these?