Should radiator fan turn on when ac is on

Dec 7, 2022 · AC running without coolant fan coming on. I have a 2012 Chevy Cruse LT. It is my understanding from a mechanic and these forums that the coolant fan should be running when the AC is turned on. It currently is not and the mechanic can find no reason why. The dealership even indicated they were not aware of any issues.

On my old Pontiac Grand Prix, the radiator fan turns on whenever the AC is on (regardless of the coolant temperature). The dual-fan will also turn on when the AC is off and the coolant temperature is high (even after the engine is shut off). I haven't paid much attention to my newer cars if this behavior is still true. Not immediately in all ...ASRDogman said: ↑. Both fans will kick in when you turn the a/c on. It's to cool the hotter freon. I'm certain the fan IS coming on, or the engine would over heat. You won't notice it driving down the road because of road/tire, wind, and other noises. And if you sitting, the engine turns off, most of the time.6 Dec 2014 ... Based on your first post I would say this may be normal for your car, but if you are not seeing the fans switch on by 101 C, I would suspect an ...Sep 1, 2020 · And is the engine overheating? Another possibility is you have a stuck open thermostat and the engine may never get hot enough to trigger the fan. Our engines have two thermostats, a 173 deg. F (78 C)main stat and a 203 deg. F (95 C) secondary. If either of them stick open it may allow too much cooling. -Todd. What temp does radiator fan turn on. Have an 09 3.5L Charger. Trying to see at what position on the coolant temp gauge the radiator fan turns on at. The fan won't turn on when I have driven the car around and let it sit running in the driveway. Needle on the gauge is at about the 12 O'clock position. I have seen the fan moving in the past.A car can overheat while idling if there is not enough coolant in the radiator or there is a malfunctioning fan, radiator or fan belt. Additionally, some cars have a fan clutch tha...That said, below are reasons/fixes for your radiator fan not working when AC is turned on: 1. Low or no coolant at all. Your radiator fan may not be working but you’d notice it’s not overheating (in many cases). The cause of this problem is that you have too little to no coolant at all in the reservoir. Note that temperature sensors are ...WTF is wrong with you!!! BMW-N your info on the electric fan was interesting and helpful. I know the fan works because it is usually on high speed turbo when the AC is on. When the AC is off it seems to operate normally and my coolant temps are normal so I think I'm ok for now on the waterpump.

I’ve got a 2013 with a 1.8L and the cooling fan doesn’t turn on at operating temp, but it does turn on with the ac. The ac clutch is messed up and sometimes stalls the engine, so I can’t have the ac running all the time. I’ve replaced this fan 5 times already and I can’t find the issue. I’ve checked the fuses and all is good.Like. Sort by Oldest first. PhLoBuS. 2194 posts · Joined 2009. #2 · May 12, 2011. I have to manually switch my LFP fan on when I use the AC. 2004 SVT Lightning. ¼: 11.30 @ 119mph - 93 octane. 782 rwhp / 794 rwtq - E85.If you’re a fan of the popular South African soap opera, Skeem Saam, you know that each episode is filled with exciting twists and turns. Yesterday’s episode was no exception, leav...By Eric November 6, 2023. Yes, the radiator fan should come on when the car starts to prevent overheating. The radiator fan plays a crucial role in maintaining the optimal temperature of a car’s engine. When the engine is running, it generates a significant amount of heat, which needs to be dissipated to prevent overheating.1. Radiator Fan Doesn’t Come On. Most commonly, the faulty fan won’t enable when it’s broken. This is caused by the motor burning out, rendering the fan …

The temp was 194 and steady. No cooling fans. Lower radiator hose cool to the touch. I revved the engine up to 2000 rpm for a couple on minutes. Temp rose to 200. Lower radiator hose finally hot, indicating that the thermostat opened. Still no fan running. I turned on the a/c with fan speed at 1. Both fans kicked on and cooled the coolant down ... My fans will only turn on when the AC is on. I have replaced the thermostat recently, coolant temp sensor, and changed both my relays for cool fan #1 and cool fan #2. I have also tested continuity for all my fuses, and they all checked out okay. And at the port where the relays should be getting power, it reads 12, indicating the relays are in ... Replacing an old AC unit or installing a new one can be a big — and pricey — job. Learn about AC installation costs with this comprehensive guide. Expert Advice On Improving Your H...The simplest method of wiring an electric fan is to use a relay that is switched on and off by the ignition switch. This method works well to cool the vehicle but the drawback is the fan will be running constantly when the ignition is on. Fan noise and added electrical system load will be present at all times.Aug 18, 2022 · The simplest method of wiring an electric fan is to use a relay that is switched on and off by the ignition switch. This method works well to cool the vehicle but the drawback is the fan will be running constantly when the ignition is on. Fan noise and added electrical system load will be present at all times. So my radiator fan will only come on when I turn the AC on. I have watched my water temp stay at 210 and start to go up (230) and the fan still not kick on. My transmission temp will also go up to 200 as high as 210 with the fan kicking on. As soon as this happens I turn on my AC and the water temp and transmission temp both start to come down.

Mckechnie field bradenton.

Reasons For Using A Fan With An Ac Unit. Yes, the fan should be on when the AC is on. A fan helps to evenly distribute cool air throughout the room, making it more comfortable and efficient. It also helps to reduce humidity levels in the space, which can make it feel cooler than if a fan was not used. Additionally, using a fan helps to ...Feb 14, 2015 · The shutters close above 40 or 45 MPH (basically once you hit sixth gear) and remain closed until the car needs the extra air flow. This means they'll close this coming Monday (here in Denver) and stay closed until the temperatures go back up - probably Tuesday evening commute. As for the main cooling fan, it will turn on and off as needed. 2012 eco. My cooling fan is not acting as it should. What I have found so far: Fan does cycle at medium or high speed with AC or Defrost turned on. Fan does not turn on at any other time that I know of, or that I can hear while driving. With engine at idle/operating temp and parked, AC and defrost not turned on: Fan does not turn on at all.Jun 18, 2016 · The best remedy for this is getting your A/C serviced. From you description, it sounds as though the system isn’t building enough pressure, and by relation enough heat to turn the cooling fans on. In other words, the system is low on refrigerant. I would confirm this by connecting A/C gauges to the system to see what the pressures are on the ... The simplest method of wiring an electric fan is to use a relay that is switched on and off by the ignition switch. This method works well to cool the vehicle but the drawback is the fan will be running constantly when the ignition is on. Fan noise and added electrical system load will be present at all times.With the growing popularity of online shopping, more and more people are turning to the internet for their grocery needs. If you’re a fan of M&S food and want to buy their products...

Nov 7, 2023 · When the air conditioning compressor is turned on, it is normal for the radiator fan to turn on due to the activation. In some cases, the radiator fan will require the radiator fan when the temperature sensor in the bottom tank of cooling fluid exceeds roughly 212F. Read More: Should The Radiator Fan Turn On When A.C. Is On? Additionally, the compromised condition of the pulley can lead to excessive wear on the belt over time, intensifying the problem. Addressing issues related to a worn or loose pulley is essential to restore smooth and quiet operation of the radiator fan during A.C. use and …The sensor on the radiator only controls the fans, it should turn on the fans at 196 - 203 F. The sensor on the engine is used by the gauge and the ECM, that is the measurement called ECT on a scanner. That temperature is controlled by thermostat, the cooling fans help transfer the heat away from the engine. Typically the fans do not run while ...The radiator fan also plays an important role when the air conditioning (AC) system is in use, as the AC puts additional strain on the engine and increases the need for cooling. Understanding how the radiator fan works and when it should turn on when the AC is on is essential for maintaining the proper functioning of a vehicle.2194 posts · Joined 2009. #2 · May 12, 2011. I have to manually switch my LFP fan on when I use the AC. 2004 SVT Lightning. ¼: 11.30 @ 119mph - 93 octane. 782 rwhp / 794 rwtq - E85. Like.Set the thermostat on your AC unit to match the temperature of your room and turn on the ceiling fan. The result will be a cooling effect without having to lower the temperature in your entire house. Use the thermostat settings for both cooling and heating and turn on both your fan and AC at the same time.16 Jun 2018 ... Could absolutely be something wrong which has the AC on all the time triggering the engine fan in turn to run full blast all the time. In my ...Faulty Magnetic Clutch. A faulty magnetic clutch can be the source of an A C fan making noise in car. The magnetic clutch is a crucial AC component that links the motor and the AC compressor. If it was broken, it might cause the compressor to turn off suddenly. When the car is utilized, or the AC is turned on, problems with the magnetic …AT WHAT TEMPERATURE RADIATOR FAN TURNS ON CHEVROLET CRUZE, CHEVY SONIC, HOLDEN CRUZEIn this video we will show you at what temperature the radiator fan / coo...WTF is wrong with you!!! BMW-N your info on the electric fan was interesting and helpful. I know the fan works because it is usually on high speed turbo when the AC is on. When the AC is off it seems to operate normally and my coolant temps are normal so I think I'm ok for now on the waterpump.

If the condenser fan doesn’t when the compressor is on, then is due to one of the following reasons: Condenser fan capacitor is bad. Fan contactor isn’t working. Fan motor is bad. Shut off your AC and check the fan capacitor, contactor, and motor if the condenser fan isn’t running when the compressor is on.

The radiator fan plays a pivotal role by drawing air through the radiator to dissipate heat. Typically, it should turn on as the engine reaches a certain temperature or when the AC is on to provide additional airflow. A fan operating solely during AC use raises potential concerns about the engine’s cooling strategy.Refrigerant Pressure Sensor INPUT to the DME is ONE of the Inputs used by DME to Control Fan Speed, ALONG WITH Engine Temp, Vehicle Speed, Cat Temp, & Battery Voltage. Your Radiator Fan or E-Fan SHOULD begin to run within 30 to 40 seconds of turning on Compressor Valve (Snowflake button on A/C Control Panel), and …Nov 7, 2010 · Totally normal. Note that if your Jeep hasn't warmed up all the way, if you turn off the AC, the fan will go off. Theoretically, if you are moving, it should turn off as well, but I don't know if that is the case, and it's kinda hard to check... Long story short, electric fan operation with AC on is normal. No worries. When the air conditioning (AC) is turned on, the radiator fan should automatically turn on to provide the additional cooling necessary. However, if you …With the AC off, when the coolant temp reaches about 194-195F both fans should run on low speed, cool the temps down a bit and then shut off and this cycle should repeat. That is proper operation of low speed. This speed is barely audible but just enough to pull some air through the radiator. When you turn on the AC both fans should run on …All vehicle ac systems are sealed from the factory with service valves made available to hvac repair people and knowledgeable diyers. If ac fails to run, the ecm knows this and does not turn on cooling fans. A dead ac system doesn't need cooling fans. This does not affect when cooling fans are needed when coolant temps rise.sw " terminal 1 " ground, and radiator fan relay no. 1 and no. 2 are turned on. radiator fan motor operation: when the ignition sw is turned on, radiator fan relay no. 1 is turned on. if at this time the engine coolant temperature is approx. 194 f or higher, the water temp. sw is turned off, radiator fan relay no. 1 is turned off.The passenger side is 227. So if both are on without the ac on then your close to overheating. The temp gauges in these cars are no where near linear. Like 12 o clock on the gauge will be from 170-220 before it will ever leave 12 o clock. So once it does start to move the temp is way high already. One fan should be enough to keep your engine ...Those radiator fans will turn on automatically when the AC is on whether they are needed or not. When they are on, they keep the coolant temperature low. Even when you turn the AC off, the temperature still might not get hot enough to trigger the radiator fan on. In most vehicles, the coolant needs to reach 225 Fahrenheit for the fans to turn on.ASRDogman said: ↑. Both fans will kick in when you turn the a/c on. It's to cool the hotter freon. I'm certain the fan IS coming on, or the engine would over heat. You won't notice it driving down the road because of road/tire, wind, and other noises. And if you sitting, the engine turns off, most of the time.

Jeep red lightning bolt.

Zona de cuba grand concourse the bronx ny.

To check to see if both fans work, turn on the AC. With the AC on, both fans should spin at full speed. If not, something's not working properly. ... i have 2013 jeep patriot, radiator fans only work with AC on. i have checked 5 relays near bumper and other related fuses in fuse box - coolant sensor has been replaced as well .As mentioned, they should be fine because both fans turned when you turn on AC. You can try to remove the passenger side fan and look near the coolant inlet hose for the switch. When you disconnect the switch the fan should turn on. You may need to turn the key to ON, but engine can be off.A faulty radiator fan control module can disrupt the normal operation of the fan, causing it to only turn on when the AC is on. The control module is responsible for receiving and interpreting signals from the various sensors and activating the fan accordingly. If the module malfunctions, it may not trigger the fan at the appropriate times.Fact 1: The Radiator Fan Should Turn On When The Ac Is On: The radiator fan plays a crucial role in maintaining the engine temperature, especially when the AC is …Italian football, also known as calcio, has a rich history and is widely regarded as one of the most passionate and exciting leagues in the world. For decades, fans around the glob...Best to avoid overheating -- not good for the 2.5 liter engine. The fans can be tested by turning on the AC even when the engine isn't fully warmed up -- both fans should run (see chart above), so no need to run the engine into the red. Share. Like. ve9aaa Discussion starter. 64 posts · Joined 2013. #11 · Sep 9, 2014.My 2013 Hyundai i10 has one fan and as far as I can see one coolant temp sensor. I replaced water pump and radiator and coolant temp sensor. When I turn on the ac the fan works and keeps the car cool. When the ac is of the radiator hoses both become same heat after a while and the overflow reservoir starts boiling over and the fan do not kick in.If you’re a fan of classic supercars, then the F40 Ferrari is likely at the top of your list. This iconic vehicle was first introduced in 1987 and quickly became a favorite among c...2012 eco. My cooling fan is not acting as it should. What I have found so far: Fan does cycle at medium or high speed with AC or Defrost turned on. Fan does not turn on at any other time that I know of, or that I can hear while driving. With engine at idle/operating temp and parked, AC and defrost not turned on: Fan does not turn on at all.AC/DC is undoubtedly one of the most influential rock bands of all time. With their electrifying performances and hard-hitting sound, they have won the hearts of millions of fans w...A radiator fan that ticks on and off uncontrollably can triggered by this scenario. Solution. Belt replacement is necessary. Engaged air conditioner compressor; When the AC compressor engaged, the radiator fan may triggered. Radiator fans circulate air within the AC condenser to prevent overheating and enhance its performance. ….

Feb 26, 2017 · 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. Totally normal. Note that if your Jeep hasn't warmed up all the way, if you turn off the AC, the fan will go off. Theoretically, if you are moving, it should turn off as well, but I don't know if that is the case, and it's kinda hard to check... Long story short, electric fan operation with AC on is normal. No worries.1 Feb 2012 ... If you don't run the AC, the radiator fans will rarely turn on this time of year. As long as it doesn't overheat when driving in traffic you ...Mar 6, 2024 · Yes, the radiator fan should turn on when the ac is on as it helps to cool the refrigerant and maintain proper engine temperature. When the ac is turned on, the compressor puts an added load on the engine, which generates more heat. The radiator fan assists in dissipating this excess heat by pulling air through the radiator. Begin by checking that all the power cords are plugged in, then locate the thermostat control for the unit and set it to your desired temperature. Next, find the unit’s main switch which will be either located on or near the front of the machine; turn this switch to “On.”. Finally, check that both fan speeds (low and high) are operational.Greetings, My radiator fan doesn’t kick in until 219 degrees F. The radiator fan does kick in at lower coolant temperatures if I run the AC. Once the fan kicks in at 219, it cools everything down to 208 and then, if I am sitting and idling, the process repeats. If I am driving down the road, the van consistently runs between 195 and 210.Consider the possibility that the fan is actually doing its work. 2). The radiator fan comes on when you activate the AC. You left the AC on. This happens more frequently than you think. In other words, when you start the car, the radiator fan will come on in response to the AC, not the temperature in the engine. 3).In this setting the cabin blower will be on, but the radiator and ac condenser fans should be off. If the rad & condenser fans are still running check the AC compressor clutch and see if its engaged, if so the climate control panel might be fubared and is constantly telling the rest of the car to run the AC regardless of the controls setting ...on May 31, 2021. Why Does My Radiator Fan Only Work When the AC Is On? If your radiator fan only works when your vehicle’s AC is on, the most likely culprit is a faulty …Oct 18, 2023 · A faulty radiator fan control module can disrupt the normal operation of the fan, causing it to only turn on when the AC is on. The control module is responsible for receiving and interpreting signals from the various sensors and activating the fan accordingly. If the module malfunctions, it may not trigger the fan at the appropriate times. Should radiator fan turn on when ac is on, How Often Does A Radiator Fan Turn On With Ac? The radiator fan may cycle on and off as needed when the AC is on. It turns on more frequently in hot weather or when the vehicle is stationary to provide sufficient cooling. Conclusion. Understanding your vehicle’s cooling system is crucial for optimal performance. Yes, the radiator fan should ... , Dec 28, 2016 · Are you saying that with the cabin heater/AC fan turned Off, the radiator fans don't come on when the OBD-indicated temperature rises above 212 F? Whether or not there's a flow problem, the fans should be turned on by the ECM when the coolant temperature is high, without having to turn on the AC. , ASRDogman said: ↑. Both fans will kick in when you turn the a/c on. It's to cool the hotter freon. I'm certain the fan IS coming on, or the engine would over heat. You won't notice it driving down the road because of road/tire, wind, and other noises. And if you sitting, the engine turns off, most of the time., 8 Jul 2011 ... Usually just turns on and off once the engine reaches operating temp in order to keep the temps stable. It also turns on when you turn the AC on ..., 1. During normal use of the veh. without AC, the Coolant Temp. Sensor and the ECM monitor coolant temp. When the coolant reaches a predetermined degree. it will send a CAN message to the AAM to turn on the aux. fans, via pin #8. When the coolant reaches another predetermined degree, the fans will be turned off., WOODY RUDY said: THE PCM commands the low speed cooling fans on when engine coolant exceeds 220 degrees. The PCM commands the high speed cooling fans on during the following conditions: engine coolant temp. exceeds 220 degrees and a\c refrigerant pressure exceeds 265 psi. If the fans don't come on at the temp. check the …, When the engine is cold the ETC switch should be closed ( that opens the radiator fan #1 relay) keeping the fan from running. When the coolent is hot, the ECT switch should be open ( closing the #1 relay) and allowing the fan to run. The second connector you found ,is probably it., My fans will only turn on when the AC is on. I have replaced the thermostat recently, coolant temp sensor, and changed both my relays for cool fan #1 and cool fan #2. I have also tested continuity for all my fuses, and they all checked out okay. And at the port where the relays should be getting power, it reads 12, indicating the relays are in ..., Radiator fan comes on high when AC is turned on. I recently purchased a used 2015 Ford F-150. I noticed that the radiator fans were always on and are pretty loud. The fans would run all the time no matter what. I took it to a shop and they said it was a faulty AC pressure switch and replaced it. I drove it home and have noticed that the ..., With the increasing popularity of streaming services, more and more sports fans are turning to online platforms to catch their favorite games. For die-hard hockey fans, finding a r..., Nov 7, 2010 · Totally normal. Note that if your Jeep hasn't warmed up all the way, if you turn off the AC, the fan will go off. Theoretically, if you are moving, it should turn off as well, but I don't know if that is the case, and it's kinda hard to check... Long story short, electric fan operation with AC on is normal. No worries. , 4wheelin Discussion starter. 675 posts · Joined 2011. #1 · Oct 11, 2019. While sitting in backed up traffic, temps based on the digital dash go up to 226. I have to turn the A/C on medium fan setting in order for the engine fan to cool the temps back down to 200-210. This is during 60 degrees outside temp. When driving, temps stay between 199 ..., When it comes to keeping your home cool and comfortable, a ceiling fan is an essential appliance. One popular brand that homeowners often turn to is Harbour Breeze. Known for their..., Your engine temperature sensor is responsible for relaying your engine temp to the ECU. Once the temp gets so hot, the ECU commands the radiator fan to come on. If your CR-V has a bad engine temp sensor the radiator fan won’t know to come on, because the ECU won’t know how hot the engine is. You’ll need to locate and test the engine temp ..., Three. Hello everyone, I am experiencing this weird issue with my 2013 Prius were the radiator fans would turn on and off continuously at full speed when the AC is turned on and the blower set to max speed (Video details on YouTube below). Also, if I set the blower speed to one bar, the fans would run at full speed without switching on …, Oct 11, 2019 · 4wheelin Discussion starter. 675 posts · Joined 2011. #1 · Oct 11, 2019. While sitting in backed up traffic, temps based on the digital dash go up to 226. I have to turn the A/C on medium fan setting in order for the engine fan to cool the temps back down to 200-210. This is during 60 degrees outside temp. When driving, temps stay between 199 ... , If the fan doesn’t turn on, you should check for a blown fuse or relay, damaged wiring, bad temperature sensors, or the wiring harness of the radiator fan. Radiator fan not turning on When AC is ON – Causes. Here are some factors that may contribute to a radiator fan not working correctly when the air conditioner is turned on. A Blown Fuse ... , Please help i have a 1998 hondaaccord 6 cylinder it keeps over heating so far i have changed thermostat, fan relays, thermostat switch i noticed my fans only turn in when the ac and or heater are on. 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 ..., Refrigerant Pressure Sensor INPUT to the DME is ONE of the Inputs used by DME to Control Fan Speed, ALONG WITH Engine Temp, Vehicle Speed, Cat Temp, & Battery Voltage. Your Radiator Fan or E-Fan SHOULD begin to run within 30 to 40 seconds of turning on Compressor Valve (Snowflake button on A/C Control Panel), and …, Nov 7, 2023 · When the air conditioning compressor is turned on, it is normal for the radiator fan to turn on due to the activation. In some cases, the radiator fan will require the radiator fan when the temperature sensor in the bottom tank of cooling fluid exceeds roughly 212F. , Conclusion. No, the radiator fan does not always run. Depending on the vehicle, the fan may only turn on when the engine is hot or when the air conditioning is turned on. Some vehicles have an automatic setting that turns the fan on and off as needed, while others have a manual setting that allows the driver to choose when to …, When the AC is on, the radiator fan’s function is crucial for maintaining optimal engine temperature and AC system functioning. Here are some frequent reasons why the radiator fan may not work while the air conditioner is turned on: Faulty Radiator Fan. The radiator fan may become worn out over time., 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., Would anyone know at what temp the radiator fans are programmed to come on? Also, what is your engine temp on the highway? I am getting ~215 degrees at 75mph on a 90 degree day with no trailer, AC on, in 10th gear. It will jump up to 225 under hard acceleration or going uphill. 2018 3.5L Ecoboost., Both fans present in the car, the primary cooling fan from the radiator and the secondary cooling fan from the air conditioning system’s condenser, should …, Should you? Here are the pros and cons: Pros: Less start/stop stress on the fan. Consistently cleaner air because of constant filtration. Keeps the ambient air at a more even temperature. Plus, learn these 21 air conditioner maintenance and home cooling tips. Cons: Higher cost. With a 500-watt motor, this can be significant! Shorter furnace ..., Start your vehicle, and let it idle for 10-15 minutes. Depending on the ambient temperature in your location, this should be long enough for the coolant temp to get hot and the thermostat to open up. Watch the vehicle and see if the cooling fan comes on. Driving your car is a good way to get the coolant temp hot., If the fans remain on for the same time, consistently, then it could be the ECU/KECM remaining on and, as the coolant temp was high, the fans continue until the control modules shut down. Then, once they are in sleep mode, the fans do not run regardless of coolant temperature., The electric cooling fan uses a direct current (DC) electric motor with a thermo switch, module or computer control to turn it on or off, depending on coolant temperature or AC operating condition. On older fan circuits, the thermostatic switch connects to battery power on one side, and to the fan motor on the other., Both radiator fans work when the AC is on but neither works when AC is off and overheats. - I know there are 3 relays for fan control. ... That is why the fan will turn off to heat up the coolant to keep the engine at a preset temp range. It is a constant read by the sensors to turn on and off the fans. ... Also both fans will come on if the ..., How Often Does A Radiator Fan Turn On With Ac? The radiator fan may cycle on and off as needed when the AC is on. It turns on more frequently in hot weather or when the vehicle is stationary to provide sufficient cooling. Conclusion. Understanding your vehicle’s cooling system is crucial for optimal performance. Yes, the radiator fan should ... , 2. High Temperature. Regardless of your vehicle’s speed, if the engine’s temperature sensor detects that the temperature is exceeding the normal operating range, it will signal the cooling fan to turn on. This helps dissipate the excess heat and return the engine to a safe operating temperature. 3., Begin by checking that all the power cords are plugged in, then locate the thermostat control for the unit and set it to your desired temperature. Next, find the unit’s main switch which will be either located on or near the front of the machine; turn this switch to “On.”. Finally, check that both fan speeds (low and high) are operational.