Will the Fan Run if the Water Temperature Sensor is Broken?
2 Answers
If the water temperature sensor is broken, the fan will not run. The water temperature sensor consists of a thermostat section and a water level control section, accompanied by a pressure reducing device in front of the electric valve and a rotary muffler heater for heating. The function of the water temperature sensor is to increase fuel injection and advance the ignition timing at low temperatures. The following are symptoms of a faulty water temperature sensor: 1. The water temperature gauge needle does not move. 2. Difficulty in starting the engine when cold. 3. The ECU cannot receive the signal for a rich air-fuel mixture. 4. Only a lean air-fuel mixture can be provided to the engine. 5. Unstable idle and difficulty in acceleration.
I once experienced a situation where the coolant temperature sensor failed while driving. When the car was on the highway, the fan didn't turn on at all, causing the engine temperature to skyrocket and nearly overheat. After that incident, I took it to a repair shop, and the mechanic diagnosed a faulty coolant temperature sensor—the signal wasn't reaching the ECU, so the fan wouldn't activate. You see, the fan relies entirely on this sensor to signal the system when temperatures rise, triggering the cooling process. If it fails, the system might enter a protective mode, preventing the fan from running randomly or shutting it down completely. During daily driving, always keep an eye on the temperature gauge—if anything seems off, pull over immediately. Leaving it unrepaired long-term can lead to severe engine overheating, damaging components and resulting in costlier repairs. My lesson? Get the sensor and related wiring checked by a professional shop as early as possible.