when i started my car it will run for about a min just fin and it will start to beep and the add coolent light comes on but the coolent is full, has this ever happened to anyone?

 

Yeah - had to replace the sensor.

 

Yeah, mine made that noise too when i broke the sensor. There was some steam coming off the top of the radiator so i tightened up the sensor but in the process of doing that I broke the sensor's top off. It's not that difficult to replace just order a new one and a seal too. All you need is the right sized wrench and you can do it very easily in 5 - 15 min.

 

my add coolant light used to go on all the time. i banged it with a hammer. now it doesn't. haha

JUST KIDDING:
I played with the sensor and wires so that everything wouldn't read anymore. BUT downfall to that was I broke my water pump and the ADD COOLANT light didn't go on, when I was leaking it all over the road. It's a good thing I didn't blow my 12a. I wouldn't be a happy camper!

 

The wire broke off of mine a while back and the same thing happened. I got a replacment for about $25 that was with shipping and handling and the gaskets.