WHAT DOES A COOLANT SENSOR LIGHT COST?

The coolant sensor is reporting to the comp. that it is running a little warmer than it should. When the gauge goes up is where our concern lies that could be a worn thermostat, low coolant, coolant sensor,, fan switch , clogged rad etc. It sounds like the fans are working when the gauge drops. Get that checked before it advances to something serious. Now its just maintenance. Good luck Frank M

Could be low on coolant, or an electrical problem with the coolant temp sensor.

give the senson on the side of the coolant bottle few taps with a stick or whatever the sensor stickes in cavaliers

Well, I recommend that you pull the error codes from the computer. Some parts shops, and many lube shops can pull the error codes. It sounds like the items you have replaced were not causing errors.
Rather than guess, get the codes. Totally less costly to focus on the system triggering the error and check engine light.

IF CAR OVER HEAT IT WONT CRANK.CHECK COOLANT FAN FUSE AND RELAY.IF ALL IS GOOD YOU HAVE FAULTY COOLANT TEMPERATURE SENSOR.IF SENSOR OKAY HOTWIRE COOLANT FAN IF RUNS FAN GOOD IF NOT REPLACE FAN MOTOR AND CHECK COOLANT FAN WIRE CONNECTOR.

THE ENGINE IT WONT CRANK IF OVER HEATED CHECK COOLANT LEVEL IF LOW ADD COOLANT.REPLACE THERMOSTAT AND RADIATOR PRESSURE CAP.IF ENGINE STILL OVERHEAT AT A STANDSTILL OR IN A LONG LINE OF SLOW MOVING TRAFFIC.COOLANT FAN SHOULD COME ON.IF ENGINE OVERHEAT CHECK TO SEE IF COOLANT TURNS ON IF NO.CHECK COOLANT FAN FUSE AND RELAY.IFBOTH OKAY HOTWIRE COOLANT FAN TO SEE IF FAN RUNS IF NO REPLACE COOLANT FAN MOTOR. IF FAN RUNS PROBLEM COULD BE PCM OR THE COOLANT TEMPERATURE SENSOR FAULTY OR DAMAGE WIRE CONNECTOR TO COOLANT FAN.USE A CODE SCANNER TO LOOK FOR PCM OR ECT FAULTS.IF EVERY THING CHECK OUT OKAY LOOK AT ENGINE OIL DIP STICK.IF IT LOOKS LIGHT BROWN OR LIKE MILK SHAKE YOUR HEAD GASKET BLOWN.MAKE SURE YOU HAVE 50/50 ANTIFREEZE AND WATER TO ENGINE TO HELP RAISE BOILING POINT.WHEN OUTSIDE TEMPERATURES HOT.

Is it the LOW coolant light? Your car is equipped with a sensor on the expansion tank (radiator overflow). Right front fender. It's there for when the car heats up. As the engine heats up and the coolant expands it racks into the reservoir/overflow/expansion tank. When the engine cools, it sucks the coolant back in. If your car was low on coolant then there's a good possibility that as it cooled, it sucked the recently added fluid in. Check that it is full to the "cold full" level by looking at the tank before you start it for the day. If it's not, then the sensor is telling you to add coolant. If it is, then the sensor in the tank may be bad.

check out the coolant temp sensor.

I'ts the low coolant sensor. I'ts located on your radiator. they are know to go out. if your coolant level is not low, just change the sensor. the sensor cost about $50.00.
good luck.

Are There two sensors??, sometimes there is one for fan and computer, and there is another just for the gauge.