What are the symptoms of a bad engine coolant temp. sensor on a 2003 Mazda MPV?

if the cooling fans are only acting up with ac on you probably have a problem related to ac pressure problem. the fans also pull air across condenser when ac pressures are high and as pressure drops they cycle off. if this only happens with ac on (hvac in defrost also)and ac works fine you may be talking about a normal occurance. if the coolant sensor is bad and it's reading low can throw off fuel managment system cause hard starts and many other symptoms. easy to check with a scan tool that reads data, start from overnight soak record data as vehicle warms up if you have any glitches/fall outs of recorded data the sensor is intermittently acting up. if your mechanic has the capability to graph the recorded data it will make capsuring intermittents easier. hope this helps