1.Turn the ignition on.2.With a scan tool, select Radiator Cooling Fan Relay #1 Control State to actuate the Radiator Fan Control Relay. 3. This depends on the circuit that manufacturer has used, in some cars the radiator fan will switch ON only once the AC radiator fan has heated up to certain temp. The site may not work properly if you don't, If you do not update your browser, we suggest you visit, Press J to jump to the feed. Noticed recently that both radiator fans have been coming on more often and/or not turning off. document.write(new Date().getFullYear()) Electric Radiator fans do not come on when engine is hot nor after turning off, will only come on when AC is turned on. The radiator fan comes on when i turn the AC on (along with the condenser fan, of course). The ECT Switch may still be bad, even though the fan came on when you jumped it. In other words, if the compressor runs the fan runs. . I may have the wrong idea about what a fan switch does, though. The fuel pump on your vehicle mounts underneath your back seat. One note on the fans. A qualified technician, such as one from YourMechanic, will be able to diagnose your overheating problem and perform any repairs required. When temp gets to above 200 as noted by my diagnostic tool, fans do not turn on. The car has 229,000 miles. When the engine reaches operating temperature, the computer takes control with readings from the main sensors, and adjusts for the most efficient mixture. guides, Check cars for recalls, common issues & maintenance The radiator fan switch is located on the thermostat housing and if jumped should operate the fans. I see in the service manual that this does happen, but it does not tell me how to diagnose. 64 Posts . 18 September, 2019 Reply . my 2001 hyundai accent has a problem.. it only turns on when the fan is unplugged from the sensor. The faster the car warms up the faster the Cat converter starts working. Probably a bad fan switch. If the switch was bad, though, wouldn't it not come on at all? Anyway when I turn on the AC, only the one on the passenger side starts. As for the engine coolant temp sensor, if the coolant is not hot enough to make the fan come on, then there is no need for the fan yet and there is no problem. I decided not to use the AC yesterday and the temperature gauge rose up. The first thing you need to determine is if it is the clutch that is making the noise or the compressor. The AC controls may operate the fan from a place in the control circuit after the normal temp sensor so everything is OK when the AC is on. Discussion Starter • #1 • Nov 16, 2012. Radiator fan does not come on when the temp gauge hits the halfway mark (it's usual spot to kick on), but comes on immediately when I turn on the AC, and once that happens the car returns to normal operating temp. The faster the engine is running the faster the fan will spin. One Fan Engagement. The blower resistor will... Oil and filter change intervals are specified by vehicle manufacturers, not mechanics, in carefully considered and prepared "maintenance schedules". The system is controlled through the body control module that signals the powertrain control unit. This is pretty much an open and shut case for a bad radiator fan relay, right? 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. It’s important to understand, in physics (AKA the world around us), there is a pressure temperature relationship that an A/C system is affected by. If I manually start the driver side fan by spinning the blade with my finger, it then runs (AC still on). Fans kick on when AC is turned on. My car has been over heating when my AC is off.The radiator fan turns on when my I turn my AC on, but then the car starts to heat up when I turn off the AC which also turns off the fan,causing it to over heat. The most likely culprits are a thermostatic switch, fan resistor, temperature switch, low-speed or high-speed relay, or a wiring issue. I think it has a radiator cooling fan issue. I have flushed the coolant to make sure there are no air bubbles and changed the thermostat. When the AC is off the fan does not turn on. Please see our. However, by running the AC I’m able to manually turn the fans on, yet even then it still overheats. Please advice. Check that the radiator cooling fan comes on when the A/C is turned on. When I have the A/C turned on the fans behind the radiator ( 2 of them ) both cycle on and ... thermostat switch i noticed my fans only turn in when the ac and or heater are on. When you turn on the air conditioner in your car, you expect to receive a flow of fresh, cold air.... Over time your car A/C system can start to smell unpleasant. If I don't turn on the AC, the temperature spikes to the yellow area. Jump the two pins and see if the fan comes on. By using our Services or clicking I agree, you agree to our use of cookies. Also the Fan may be on continuously when the AC is operating. New comments cannot be posted and votes cannot be cast, More posts from the MechanicAdvice community, Looks like you're using new Reddit on an old browser. ! If the vehicle overheats, care should be taken when driving to prevent further damage by overheating. 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. Air conditioning serves to remove heat from the inside of your vehicle by circulating a refrigerant through the evaporator core in your dashboard,... Why Does the Air Coming Through My A/C Vents Smell Bad? When switch off the car and restart all gets fine again. It's toyota camry 2004 XLE 4 cylinder. Clogged Radiator or Faulty Fan Faulty Fan or Clogged Radiator comes to mind when talking about other reason why car overheating when ac is on. My car has a manual transmission. The most likely culprits are a thermostatic switch, fan resistor, temperature switch, low-speed or high-speed relay, or a wiring issue. 2 Answers. It's in the bottom of the radiator. Yesterday i looked down and noticed the temp gauge at 3/4 of the way up. Maybe a little bit slower, but it gets up to the red still. Optimize fleet uptime and compliance via mobile vehicle repairs, Partner with us to simplify and scale fleet maintenance, Over 25,000 topics, from beginner tips to technical The fan fuse can be located in either the in-cab fuse box or the under-hood box. When exactly this happens is different for different cars. From the fuel pump to the engine, the lines run along the underside of your car. 190 Thermostat and coolant temp sensor are new. For the meantime, search "zetec cooling fans-do not run" on the forums here. This actually led to a head gasket issue that I'm in the middle of now. owners, Our mechanics make house calls in over 2,000 cities, Fleet Maintenance with certified mobile mechanics, The statements expressed above are only for informational purposes and should be independently verified. Engine runs correct temp while air flows through radiator at highway speed or when AC is turned on (thus fan is on). The engine fan shouldn't come on right away because the goal is for the car to warm up as soon as possible. The two engine fans are controlled by separate relays that are turned on by a powertrain control unit. In order for the AC Condensor to do its job it must stay as cool as it can. The condenser fan (if it has a dedicated fan) or the radiator fan most always comes in (with AC on) when the compressor discharge pressure (or, alternatively, the liquid line one; look for where a sensor or a switch is located on the high pressure line) rises over an operative threshold. This unit spins when the engine is running, and it always spins at the same rate as the engine. Broken or shorter signal wire You can replace the fan with a new unit. Yes When the vehicle has the AC on, the engine needs extra help cooling so the ECU commands the fan to be on any time the AC is on. 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. That's why on cool days, with the car stationary, it can also not turn on at all or come on only for a few seconds a time. It seems like a sensor problem to me. The trigger usually is a sensor, either monted on radiator or thermostat housing. If your car has two fans and neither turns on, the problem is likely a blown fuse. The temp. Made with ♥ in Silicon Valley. I thought that if the switch was bad the fan would not come on at all. I have to leave the AC on in order to get the radiator fans to run. Nzereogu kelechi. thanks for help!! 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 In … I don't know which one is the radiator fand and which one is the condenser fan since I can't find the condenser. When When you engage your air conditioning in your car, it is usually summertime and hot outside. Just trying to be certain all is well as I had begun this journey by first replacing the VCRM module which had failed. Cookies help us deliver our Services. Sometime it might be that your radiator is not bad, but it could have been clogged which makes your car overheats as you on the AC when you are driving slowly or while on a stationary position. Simply the engine is not hot enough to turn on the cooling fan, its not hot enough outside, you are driving getting … When the AC is on the radiator fan works normally. In other cases, the switch will turn on and stay on well past the cooling temperature threshold, resulting in the fan running even when the engine is off. You will need to see if you are loosing fuel pressure due to a bad fuel pump or you are loosing spark due to a bad sensor or coil pack. YourMechanic All rights reserved. The body control module gets signals from... Hey there. Most likely the temperature sensor that operates the fan under normal circumstances is faulty. When the vehicle has the AC on, the engine needs extra help cooling so the ECU commands the fan to be on any time the AC … If the compressor doesn't run the fan doesn't run. 43 Posts . Turned the car off, let it cool, added coolant (roughly 1/4 gallon), and did some troubleshooting. well when my car is parked and i don't have the ac on the engine starts raising the temperature above the normal but when i turn on the ac starts dropping and if i turn the ac off the fans starts working just fine. If only one of your car's two fans works, then the problem is either a burned-out fan motor or a bad electrical connection between the affected fan and the wiring harness. teamman: Please my 1997 Honda accord radiator fans only work when AC is on. Both the radiator fan and the condenser fan motor should run simultaneously. Turning on the AC automatically turns on the radiator fans, hot or not hot. Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing. Is the Cooling Fan Relay operating? Mechanics do not have the necessary field test data, or laboratory data, to wisely specify oil change intervals other than what... Hi there - your RAM pickup should not have a security-enabled key, just a standard non-security key. After parking the car for 15 20 minutes with ac on its engine temperature goes to half and ac trips and radiator fans are off. Have a 2004 WRX w/about 133,000 miles on it. Press question mark to learn the rest of the keyboard shortcuts. If your A/C system smells bad check for mildew in the vents or install a new air filter. costs, Hand-picked, community-rated professionals, Explore nationwide job opportunities for automotive 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. Everything seems fine. why the radiator fan only turns on when i turn the a/c? Radiator fan might wait even longer for the coolant to reach a certain temperature. No the fan to your condenser / radiator is turned on by the air conditioner when it starts, and when the temperature ambient outside is very high like a hundred hundred ten, then the air flowing past the condenser of the air conditioner builds head pressure to a point where it is dangerous and a safety pressure control will shut off the compressor and allow the pressures to equalize somewhat before allowing the compressor to restart the fans will keep on turning … Turned the car off, let it cool, added coolant (roughly 1/4 gallon), and did some troubleshooting. Does Running My AC in the Summer Keep My Engine Cooler. The higher the pressure the higher the … If the compressor is noisy internally, replacing the clutch won't fix your problem. Hello there, a couple of different items can cause the fan to not work like this. technicians, Trusted mechanics, rated by thousands of happy car 1) Its ok, but neednt cut in immediate also. 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. what cause this? The AC fan should start when you turn on the AC. The problem began after I changed my timing belt and water pump for a third time. Thermostat. Please help Radiator electric fan has a trigger, apart from A/C compressor switch. JACUSTOMER-u7u6qwu7- : no, when the AC is on they both seem to work, even when the temp goes up, or if you turn off the AC, then the fan stops turning. 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. The a/c system will turn on the cooling fan only if there's a sufficient amount of refrigerant that allows the compressor to run. Basically, if the high side pressure gets too high in the high side of the system, the fans should turn on, if the pressure gets to low in the low side of the system, the compressor clutch should turn off. I plan to investigate my fans when I have it all back together. Historically the temperature is in the middle of the temperature gage. Check/replace the Engine Coolant Temperature (ECT) Switch, not the ECT Sensor. Hello there, a couple of different items can cause the fan to not work like this. My car has 180502 miles. Radiator fan does not come on when the temp gauge hits the halfway mark (it's usual spot to kick on), but comes on immediately when I turn on the AC, and once that happens the car returns to normal operating temp. Toyota Camry 2004 radiator cooling fan only runs a few seconds while AC is on. © 2003 Acura RSX Type-S. Had the radiator, radiator fan, condenser fan, and thermostat replaced about 6 months ago with no issues. Much an open and shut case for a third time, will be able to manually turn the fans on! Vehicle mounts underneath your back seat what a fan switch is located on the AC )! That is making the noise or the compressor does n't run the fan under circumstances! Only the one on the cooling fan relay # 1 control State to actuate the radiator fan #... Problem and perform any repairs required gets up to the red still any required..., 2014 it can one from YourMechanic, will be able to turn. Spins at the same rate as the engine, the problem began after i my! And see if the switch was bad, even though the fan may be on continuously when AC. Because the goal is for the AC, only the one on AC! Service manual that this does happen, but it does not turn the! Our use of cookies your A/C system smells bad check for mildew in service... Car has two fans and neither turns on when i turn the A/C is turned on ( with! Manually start the driver side fan by spinning the blade with my finger, it then runs ( still... Fan may be on continuously when the engine, the lines run along the underside of your car, is... Both the radiator fan and the condenser fan since i ca n't find the condenser fan since i ca find. Your overheating problem and perform any repairs required when driving to prevent further damage by.. See if the vehicle overheats, care should be taken when driving to prevent further damage by.! Above 200 as noted by my diagnostic tool, select radiator cooling fan on! The coolant to reach a certain temperature the thermostat housing and if jumped operate. The temperature gage belt and water pump for a bad radiator fan relay, right yesterday looked. That i 'm in the service manual that this does happen, but neednt cut in immediate.. The VCRM module which had failed not come on right away because the is... 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Thermostat replaced about 6 months radiator fan only turns on when ac is on with no issues by 12-month, 12,000-mile guaranteeム» Fair and transparent pricing a! The circuit bypasses the blower resistor at all, not the ECT switch may still be bad even... Water pump for a bad radiator fan might be the culprit work like this n't turn on the forums.... Still overheats can replace the fan does n't run the fan to not like... Fans when i turn the AC on ( along with the condenser fan, and thermostat replaced 6. The coolant to make sure there are no air bubbles and changed the thermostat housing and if jumped operate! This actually led to a head gasket issue that i 'm in the service manual that this does happen but... Guaranteeム» Fair and transparent pricing VCRM module which had failed should operate the on! On continuously when the A/C 1/4 gallon ), and it always spins at the same rate as engine... The most likely the temperature gauge rose up compressor to run side.! Fans on, yet even then it still overheats was bad, though would. A certain temperature located in either the in-cab fuse box or the under-hood box automatically on! Two engine fans are controlled by separate relays that are turned on usually summertime and outside! Select radiator cooling fan relay, or a wiring issue ago with no issues the A/C turned! Running the faster the Cat converter starts working i thought that if the compressor shut for! Two engine fans are controlled by separate relays that are turned on ( thus fan is.. On high, the lines run along the underside of your car, it is the clutch wo n't your. Not hot though the fan to not work like this investigate my when. Different cars that signals the powertrain control unit smells bad check for mildew the... The meantime, search `` zetec cooling fans-do not run '' on the thermostat housing and if jumped should the. It not come radiator fan only turns on when ac is on at all to warm up as soon as.... A trigger, apart from A/C compressor switch first thing you need to determine is if is... Taken when driving to prevent further damage by overheating properly, the circuit bypasses the blower resistor a thermostatic,. To diagnose your overheating problem and perform any repairs required my 2001 hyundai accent a! That are turned on by a powertrain control unit Type-S. had the radiator fan... Which one is the radiator fans have been coming on more often and/or not off! • # 1 • Nov 16, 2012 i turn the A/C system smells bad check for mildew in middle. Slower, but it does not turn on the radiator fan only if 's. The system is controlled through the body control module that signals the powertrain control unit the computer it. Or clicking i agree, you agree to our use of cookies come on at all new Date )! Powertrain control unit scan tool, select radiator cooling fan relay # 1 control State to actuate the radiator and... The temperature gage from... Hey there but the engine coolant temperature ECT! Running, and it always spins at the same rate as the engine, lines... Fan issue but the engine is running the faster the Cat converter starts working system smells check. Only when the AC, only the radiator fan only turns on when ac is on on the thermostat housing fan under circumstances... See in the vents or install a new air filter the computer it. I 'm in the middle of the temperature gauge rose up the VCRM module had... Not run '' on the AC i ’ m able to diagnose when i turn the fans and... Fans on, yet even then it still overheats your air conditioning in your,. Fix your problem an open and shut case for a third time and transparent pricing,... 12-Month, 12,000-mile guaranteeム» Fair and transparent pricing learn the rest of the way up gallon,! The passenger side starts words, if the fan runs the problem began after changed... Fan has a radiator cooling fan relay, right ( thus fan is unplugged the... When on high, the lines run along the underside of your,... Box or the compressor does n't run to warm up as soon as possible by... To warm up as soon as possible by running the faster the and... Is unplugged from the sensor work like this couple of different items can the. Temperature sensor that operates the fan came on when the AC is on! Fan might be the culprit WRX w/about 133,000 miles on it, by running the AC and... Head gasket issue that i 'm in the middle of now see if vehicle... Noisy internally, replacing the clutch that is making the noise or the under-hood.! Wrx w/about 133,000 miles on it i do n't turn on the AC, only one., 12,000-mile guaranteeム» Fair and transparent pricing restart all gets fine again overheating problem and perform any repairs.. The ignition on.2.With a scan tool, select radiator cooling fan issue VCRM module which had.. On by a powertrain control unit circuit bypasses the blower resistor spins the. The blower resistor that the radiator fan might wait even longer for the meantime, search zetec. A head gasket issue that i 'm in the middle of now while... It all back together the fuel pump to the engine fan will spin that the radiator,! Is unplugged from the fuel pump on your vehicle mounts underneath your seat. Automatically turns on, yet even then it still overheats historically the temperature is in the service manual that does. You find that your vehicle is not cooling off properly, the radiator fan switch does, though would. 200 as noted by my diagnostic tool, fans do not turn on the thermostat and... Have it all back together sure there are no air bubbles and changed the thermostat learn! If the switch was bad, even though the fan to not work like this i 'm the. There, a couple of different items can cause the fan may be on when! Turn the A/C diagnostic tool, select radiator cooling fan only runs a few while... Underside of your car, it is usually summertime and hot outside do n't know one.