xxSleepy562xx

Hey guys, after a long while of not having any overheating or temperature rises issues. My car decided to get near fully hot temperature yesterday. I drove fine the whole day until I got home and noticed the temperature. I've already checked for leaks on the coolant hoses, around the thermostat, water pump, and checked my oil. Everything seems to be fine, so I'm thinking is it my coolant temperature sensor that's messing with me? Because I replaced my alternator a while ago, and someone accidently messed with it while I was under the car and ever since then my temp gauge wouldn't always be accurate or would jump up and down.