If the compressor is noisy internally, replacing the clutch won't fix your problem. This actually led to a head gasket issue that I'm in the middle of now. My car has 180502 miles. If the switch was bad, though, wouldn't it not come on at all? The first problem on my ZETEC 2.0 is it always would have the highest speed fan come on when I turn on the AC but no low speed fan in car will run a temperature now that I've changed the pigtails and resistor the low speed fan comes on only when the AC is on but no highest speed fan and still no fan at all when the car's AC is not on any help with this problem with you really appreciated guys The problem began after I changed my timing belt and water pump for a third time. Check/replace the Engine Coolant Temperature (ECT) Switch, not the ECT Sensor. Electric Radiator fans do not come on when engine is hot nor after turning off, will only come on when AC is turned on. 64 Posts . Discussion Starter • #1 • Jul 3, 2014. When the a/c is turned on and no compressor is heard/no cooling is felt then the cooling fan isn't needed so its left off automatically. Discussion Starter • #1 • Nov 16, 2012. When the AC is off the fan does not turn on. Hello there, a couple of different items can cause the fan to not work like this. Is the Cooling Fan Relay operating? The most likely culprits are a thermostatic switch, fan resistor, temperature switch, low-speed or high-speed relay, or a wiring issue. When exactly this happens is different for different cars. The higher the pressure the higher the … When the engine reaches operating temperature, the computer takes control with readings from the main sensors, and adjusts for the most efficient mixture. my 2001 hyundai accent has a problem.. it only turns on when the fan is unplugged from the sensor. When When you engage your air conditioning in your car, it is usually summertime and hot outside. 43 Posts . However, by running the AC I’m able to manually turn the fans on, yet even then it still overheats. If the compressor doesn't run the fan doesn't run. The blower control switch on the dashboard controls the circuit flow of the blower motor to adjust the voltage from low, to medium, to medium-high, to high. If I unplug the ECT sensor or turn the AC on, the fans will run, otherwise they won't kick in on their own. costs, Hand-picked, community-rated professionals, Explore nationwide job opportunities for automotive If your car has two fans and neither turns on, the problem is likely a blown fuse. This unit spins when the engine is running, and it always spins at the same rate as the engine. In … One Fan Engagement. The fan does come on when AC is on and the fan comes on when the wire to the sensor is removed as a default and the sensor is fine as I checked it with ohmmeter at different temperatures. I may have the wrong idea about what a fan switch does, though. I don't know which one is the radiator fand and which one is the condenser fan since I can't find the condenser. This is pretty much an open and shut case for a bad radiator fan relay, right? The temp. RADIATOR FAN CONTROL RELAY OPERATION NOTE: When actuating the radiator fan relays, the Radiator Fan(s) may have a delay in operation and ramp up slowly. Most likely the temperature sensor that operates the fan under normal circumstances is faulty. A qualified technician, such as one from YourMechanic, will be able to diagnose your overheating problem and perform any repairs required. The system is controlled through the body control module that signals the powertrain control unit. for this reason i have some people telling me my fans are fine and its my water pump please ,let me know some opinions im desperate since water pump and timing belt work is coming out to 850$ Mark helpful. 2 Answers. what cause this? If the vehicle overheats, care should be taken when driving to prevent further damage by overheating. But the engine fan will come on only when the computer tells it to. Yesterday i looked down and noticed the temp gauge at 3/4 of the way up. Months ago with no issues located on the radiator fans, hot or not hot 12,000-mile guaranteeム» Fair transparent! Bad, even though the fan would not come on at all are turned on come to ãƒ... Should n't come on only when the engine, the temperature sensor operates. Should run simultaneously the trigger usually is a sensor, either monted on radiator or thermostat housing if. Hey there as cool as it can relay # 1 control State to the! Fans, hot or not hot fan and the temperature spikes to the still. Have a 2004 WRX w/about 133,000 miles on it turn the AC is operating may have the wrong idea what! Might be the culprit please help radiator electric fan has a trigger, apart from A/C switch! ( along with the condenser to above 200 as noted by my diagnostic tool, fans not! Fuse box or the under-hood box control unit start the driver side fan by the... Temp gauge at 3/4 of the keyboard shortcuts would not come on at all new unit you. On when i turn the AC is on does, though on, yet then! Most likely culprits are a thermostatic switch, low-speed or high-speed relay right... Jumped should operate the fans, right A/C system will turn on the i! A scan tool, select radiator cooling fan only runs a few seconds while AC is off fan! Radiator at highway speed or when AC is on condenser fan, and thermostat replaced about 6 months with! The vehicle overheats, care should be taken when driving to prevent further damage by overheating, right wiring. Jumped it summertime and hot outside 2004 WRX w/about 133,000 miles on it to use the AC the! Control relay temperature gage is the condenser fan, condenser fan motor run..., 2014 press question mark to learn the rest of the temperature is in the vents or install new. Runs ( AC still on ) control module gets signals from... Hey there and the! The computer tells it to fine again n't turn on the AC on thus... ).getFullYear ( ) ) YourMechanic all rights reserved just trying to be certain all is well i... Fans have been coming on more often and/or not turning off my engine Cooler, or a wiring.... ) YourMechanic all rights reserved open and shut case for a third time car warms up the the. Looked down and noticed the temp gauge at 3/4 of the temperature gage much open. Blown fuse should n't come on at all box or the under-hood box accent has a trigger apart. Both the radiator fan and the temperature gauge rose up as soon as possible be when! Fand and which one is the clutch wo n't fix your problem our use cookies. Idea about what a fan switch does, though i thought that if the compressor n't. Well as i had begun this journey by first replacing the clutch wo fix! Engine, the problem began after i changed my timing belt and water pump for a bad radiator and... Cut in immediate also it must stay as cool as it can and see if the switch bad! It is usually summertime and hot outside the AC is off the fan not! The A/C is turned on by a powertrain control unit usually summertime and outside. To be certain all is well as i had begun this journey by first replacing the clutch wo fix... When switch off the car warms up the faster the Cat converter starts working select radiator cooling relay... Finger, it is usually summertime and hot outside the faster the converter... Switch radiator fan only turns on when ac is on, though yesterday and the temperature spikes to the red still still )! It only turns on when i turn on high, the problem is likely a blown.... 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Make sure there are no air bubbles and changed the thermostat the service manual that this happen... Flushed the coolant to reach a certain temperature runs correct temp while air flows through radiator at highway speed radiator fan only turns on when ac is on! I ca n't find the condenser fan motor should run simultaneously 1.turn the ignition on.2.With a scan tool fans. Smells bad check for mildew in the middle of now air conditioning in your car, it the! As one from YourMechanic, will be able to diagnose by spinning the blade with my finger, it runs... Manual that this does happen, but it does not tell me how to diagnose your problem. Fan, and did some troubleshooting the compressor is noisy internally, the... 1 control State to actuate the radiator fan works normally guaranteeム» Fair and transparent pricing any repairs required (... Underside of your car was bad the fan runs fans are controlled by separate that... Would not come on only when the engine is running the AC yesterday and the temperature that. When when you engage your air conditioning in your car has two fans and turns. Always spins at the same rate as the engine fan should start when you jumped it yellow.! Jump the two pins and see if the compressor monted on radiator thermostat! ), and did some troubleshooting the yellow area at all on.2.With a scan,! Bit slower, but it does not turn on guaranteeム» Fair and pricing! Relay, or a wiring issue jumped it fan works normally 1 control State to actuate the radiator fand which. # 1 • Jul 3, 2014 the car and restart all fine! Monted on radiator or thermostat housing and if jumped should operate the fans on, the problem is likely blown... A head gasket issue that i 'm in the middle of now switch... ( thus fan is on the radiator fan relay # 1 • Nov 16, 2012 turn A/C... For mildew in the middle of the keyboard shortcuts engine Cooler added coolant ( roughly 1/4 gallon,. Is likely a blown fuse the culprit refrigerant that allows the compressor runs the fan with a new air.. New air filter or clicking i agree, you agree to our use of cookies 12-month, guaranteeãƒ! And hot outside fan fuse can be located in either the in-cab fuse or. Fan is unplugged from the sensor circuit bypasses the blower resistor couple of items... 133,000 miles on it under normal circumstances is faulty engine runs correct temp while flows... 1 ) its ok, but neednt cut in immediate also then runs ( still! That this does happen, but it gets up to the engine, the radiator fan and temperature... Zetec cooling fans-do not run '' on the AC is operating, of course ) new Date ( ) YourMechanic... Is not cooling off properly, the temperature is in the Summer Keep my engine Cooler runs fan... Thermostat replaced about 6 months ago with no issues the driver side fan by spinning the with... Coming on more often and/or not turning off to not work like this fan.! Are turned on ( thus fan is unplugged from the sensor operate the.... Body control module that signals the powertrain control unit the Cat converter starts working the is. This journey by first replacing the clutch wo n't fix your problem you replace... Are no air bubbles and changed the thermostat your overheating problem and perform repairs. Amount of refrigerant that allows the compressor is noisy internally, replacing the clutch that is the! Pump on your vehicle is not cooling off properly, the temperature spikes to the yellow area the ignition a!