Why did my 2005 PT Cruiser temperature gauge dropped to cold while driving

Possibly just the temperature sending unit. Car run ok?

Yes my car continue to run, the check engine light came on.I got off the free way drove slowly and went home. I didn't drive the PT today. I just had my timing belt and water pump replaced last week.

The sending unit is usually a brass plug somewhere on the top of the engine with a wire or electrical plug on top of it. The mechanic might have just brushed it loose.

If you just had a water pump then they had to ad a lot to the cooling system. Make sure the fluid level is full. There may be 2 sensors, one to sense the coolant temp and it will turn on the cooling fans it will have 2 wires going to it. The other one, is the sending unit like ytlas said. It will only have one wire going to it.

My 2005 Pt Cruiser turbo manual 5 speed shuts completely off while driving. Wait 5 min restarts? Replaced IAC , New timing chain, tune-up, water pump. Need help car is in excellent condition, oil changed every 3 to 5000 miles Very well maintained. Only 93,000 miles