You may need a waterpump. Run the car without the a/c; the fans will run at low speed when the temp gauge reaches M for a minute or so. The fans should stop after a few minutes and repeat. It's also possible the high speed fan circuit has a problem, or one of the fans has failed. The high fan comes on when the engine is warmed up and the weater is hot with a/c on. You will hear it cycle high/low if you have the car idling with a/c on.
