My add coolent light is comming on like 4 seconds after I start the car and the buzzer is going off. Is this sensor the wire above the radiator? Cause I know its full. And if I i play wiht the wire it will stop, then come back on moments later.

 

Bad, dirty, loose connection. Try cleaning. If that doesn't work, hard wire it.

 

Check the coolent level in both the upper and lower rad caps and make sure it's full. Is this on a cold start or a hot start?

The Add Coolent light/alarm is not called the "Buzzer of Doom" for nothing.

Z
(cooked a motor last year because of low coolant)

 

If you want a temp fix if your sensor is bad/or some other reason you can just ground it. But check your connections and wires first, it's quite a tiny little wire and looks like it could break easily.

 

Bleed the air out of the system. This happened on my car. There is an air bleed valve on the top of the passenger side of the radiator.

 

Woops. Didn't read your entire post befor I posted. Sounds like a bad connection. That sensor grounds when water hits it. Test it by pulling it out, and grounding it against something metal, and see if it goes off.