I have a low coolant light and tem. is under 210 and coolant is full.

Try tapping on the coolant bottle with a rubber mallet near the bottom and see if the warning goes out. If it doesn't, remove the coolant bottle, wash it out with a garden hose sprayer, then fill it with hot water and shake it for a minute to clean out any garbage inside. The sensor is probably just sticking due to buildup. Once cleaned, it'll most likely work fine.

Yes you can unplug it but must jumper the connections to fake computer the bottle is full but may be the float is stuck inside the bottle lightly tap on it with a hammer and see if warning goes away.