Repeat.. Also the unit I've very warm to touch. As the fan speed is one of the most frequently adjusted settings of the air conditioning system, the blower motor resistor is put under constant stress, which can cause it to eventually fail . When dry or cooling operation is activated with the auto fan speed setting set to ON, the SMELL PROOF operation starts and removes stagnant odor from the indoor unit before air is discharged. mostly happens within first 10 minutes of driving. This includes F150 Harley Davidson, King Ranch, SVT Raptor, FX2, FX4, Platinum, Lariat, and STX editions. Once it reaches the 70 F setpoint, it starts alternating between FAN blowing ambient air … I am also assuming that it's ok to run the CPU at 100% 24/7 because of the durability of the PM. Reply: I'd … The blower motor resistor in your BMW is part of the HVAC system, or the heating and air conditioning system. Not exactly the same situation, but the fan in my 1996 993 fluctuates when using the AC MAX switch (large snowflake), however, it doesn't fluctuate when the regular AC switch (small snowflake) is used. 2. The loud sound could come from your Fan Clutch for the same reason your fan stays on. In fact, some of the air conditioners are provided with a control in which the fan also stops working for the purpose of energy-saving and one can use the ceiling fan at low speed to maintain the airflow and is helpful in saving energy since the energy consumption of ceiling fan is less as compared to that of AC fan. Perhaps your ducted AC is doing the same for various reasons. The A/C Heater speed control has stopped working on the 1 and 2 position. When you cut the motor off the fans continue to run on high speed until the timed power cuts off. Rear A/C controls continue to work fine and cold air is blowing out well. Is your fan speed control a variable speed or does it have individual set speeds that can be selected for example, Off, 1, 2, 3, and so on? Average failure mileage is 15,000 miles. Activating the Automatic Fan Speed checkbox on the main screen enables fan control. Our TT is only 19' and the air force is way too much. ... 0:30 and the fan ran for (+)(-)2:00, This is a brand new unit with 121.5v going to it on a dedicated circuit. that would explain changes in noise - if that is what the tech was talking about. Exterior doors are hard to open or do not close securely. The air conditioner manufacturers have the minimum temperature set in the mid-70s for a reason. Re: Intermittent blower motor operation. and the compressor is the only item that cycles. Just had a new rear rooftop Dometic heat pump installed. This got power to the units, but fan speed was very weak at highest setting barely noticeable that air was coming out at all, the unit was set to the swing function but that function never engages, and air never warmed up with the thermostat set to 88 degrees, HVAC installer back, drained and weighed refrigerant (it was a couple lbs low). Those are just some of the reasons why your RV AC fan isn’t working. If a blend door for cool air is open only part way, the fan motor might generate a mighty roar, but only a small amount of AC air will make its way into the interior. Idle, when guage is not fluctuating - low: about 35 or so, high side about 120. You can check behind the dash and inspect that the contact points of the switch aren't dirty, damaged, or shot. The fan comes on, then the compressor kicks in as it should, but will shut off again in less than 10-15sec. Last night, I has 73 F / 60% RH in the room, so I turned the system onto COOL mode with the lowest fan speed and 70 F. Over a span of a few hours, it lowered the temperature to 70 F and RH to 50%. If any of these is noticed: Inspect the low- and high-port-tubing terminations. I have the WT trim so there is no automatic climate / fan control. The heater A/C fan speed fluctuates, starts and stops randomly, and sometimes does - Answered by a verified Buick Mechanic We use cookies to give you the best possible experience on our website. If it is not set, the old fan … Fan will run and the slow down and then speed back up . 2008 santa fe ac/heat fan/blower jumps up and down. Often it will blow harder when I first start the car but slow down to a trickle of air within 20-30 minutes. Whether the old fan control or the new Advanced Fan Control strategy is used depends on the Advanced Fan Control checkbox on the FAN CONTROL tab of the CONFIGURE window. Return or relief fans operate near 100-percent speed most of the time. When the AC compressor kicks in ( it runs intermittently)- the electric fan that pulls air across the radiator and AC condenser, jumps up to high speed ( and both fans come on under the hood)- is this what you hear ? The module decides on the fan speed depending on how close the target temperature is to the current cabin temperature. If you start at the blower motor, and check resistance in the circuit, you will find the problem in … Question: humming AC, fan speed varying (June 26, 2015) Bill said: My ac unit is cold . If the fan blower on your Ford E-250 begins to fail, there are two likely problems. Let us know what engine size your F-150 has so that we can possibly get more information for you. Jan 14 2016, 6:47pm. It seems to be cycling on and off on the A.C setting too fast. the ac control head or the blower motor resistor. Outside Temps above 90 degree F. Vehicle is being driven in the city, all systems appear to be normal. Accessing the fan blower's motor or replacing the fuse should only take about five minutes. Either the motor is malfunctioning and will need to be replaced, or more commonly the fuse has blown out. Mine blows so hard even on low speed. bumps also affect it so all the pot holes in minneapolis are making my blower jump all over the place! Before this time (about 2 days ago), my rated speed was 1.8GHz. no matter what setting the "knob" is on, the blower changes by itself. Even when I set the speed manually it changes on its own, and it does NOT regulate the cabin temperature properly. The closer the temperature is, the lower the fan speed, with a minimum of notch 3 (for those with the display type CCU, the older automatic CCU has less fan speed notches). How do I go about checking this out? The 2010 Nissan Titan has 1 problems reported for fan speed fluctuates. On the days it does work I seem to have no control over the fan speed. There also may be problems with the other AC parts that help make the fan run. When the voltage fluctuates largely, operation can stop to protect the air conditioner. 2014 Silverado Fan Speed. The most common symptom of a faulty blower motor resistor is a blower fan that only works on one speed, usually high. Fan motor maybe? So I wanted to know if I'm on the right track. Regarding the subquestion about the fan speed fluctuating which was asked under the subject "Clutch Slipping at 40K." Fan selector switches can go bad just like a window switch or a door lock switch, which means that even though the rest of the system is working as it should, the switch isn't triggering the right action. Professional Heating, Air Conditioning Repair & Installation Services. Medium or High fan speed this doesn't happen. Randomly, the Front Blower Motor will stop moving cold air. Jun 21, 2011 #1. Return- or relief-fan speed fluctuates widely and/or rapidly. The fan will only operate at speeds 3 and 4. The blades are out of balance, the motor doesn't perform well, or the blower doesn't put out the air flow you need. Thanks, DustoMan - 2009-2014 Ford F-150 Looks like you're getting some good suggestions. Now it fluctuates randomly. The fan runs some times, but not constantly (so I assumed it was ok). The Clean Air Act Inc. is a professional heating and air conditioning company who serves the greater Portland, OR area. I just replaced my a/c fan with a factory one that works perfectly fine as well.. Is it just the blower that is intermittent or is the AC compressor engaging also intermittent? It's never ever shut down because of heat problems. This can be annoying, but troubleshooting is easy. Is the switch going bad? Thanks. When your AC turns on, it puts a load on the engine (the engine is responsible for turning the compressor, which builds pressure in the system, which allows low-pressure, gaseous refrigerant to be turned into high-pressure liquid and used in your cooling system. The dealer said oh ya it most likely do to that, so $1500.00 later for a … When the load on the AC is reduced (like lower the fan speed) the low pressure switch will cycle, at which time the low side slowly rises and high side slowly falls, about 20 - 30 seconds before it kicks on again. When running my AC’s, I put the fans on manual speed, normally at med. The system requires a motor, called the blower motor, which powers the fan utilized to propel air from your cabin vents. This is not a malfunction of the air conditioner. I have checked the fuses and relays and they all look okay. When fan speed is changed via the knob on the instrument cluster, the blower motor resistor changes setting, which changes the speed of the blower motor. By continuing to use this site you consent to the use of cookies on your device as described in our cookie policy unless you have disabled them. Took it to the dealer they said it was because mu AC was out which does not make since. I am wondering if I could adapt a variable speed control (rheostat)to have more control over fan speed. 2. It is best to charge on a 85*F+ day and the engine speed should be at 2,000 rpm, the blower at maximum, AC on of course, and a door open, you really want the system to be working hard. there is onlt two things that would cuase you fan speed problem. During the summer a couple of times I'd notice the fan speed when running the AC would drop all on it's own. 95% of the time it is the blower motor resistor which is located on the passenger side under the dash, remove the cover panel and you will see the blower motor and right next to … The 2009-2014 Ford F-150 with automatic climate control may have a problem with frequent fan speed changes when using the heater or air conditioner. @bhurry turn your AC off and see if the fan still stays on. I have noticed a few times my fan has a mind of it's own. It has a humming sound now. How this system works: First, understand that this problem isn’t tied to just one system – it’s a combination of different things. No matter how many times (or position) the fan speed knob is moved, the front blower motor fails to respond. After the usual 2 min. RV AC Fan Not Working: There are a lot of reasons why your RV AC fan does not work. Building differential static pressure fluctuates widely and/or rapidly. I have non ducted Dometic and when set on low fan speed under some conditions it will occasionally go through a defrost cycle by dropping the compressor and raising the fan speed. Has anyone modified their fan speed on their roof top ac? Visit our about us page to learn more about our company! A/C temps fluctuates while driving Posted by mizak82, Jun 21, 2011. At 2K rpm, high side 175, low side at about 28. 24/7 because of the air conditioner that would cuase you fan speed checkbox the... 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