Asked on Jun 09, 2012

A/C question: My outside unit runs, but no air is being pushed through the vents in the house.

by Scott
It has been about a year since my last tune up, and I am wondering if a tuneup might be all I need, in order to avoid a service call and diagnostic fee and any other charges that may come along with all that. Thanks as always for your input!
  62 answers
  • Walter Reeves Walter Reeves on Jun 10, 2012
    Sounds like something amiss in the air handler (fan unit). Is it in a place where you can get close and listen to it?
  • KMS Woodworks KMS Woodworks on Jun 10, 2012
    there may also be some clogging of the coil...time to look a bit closer at the fan / coil area.
  • The inside fan is not running it can be one or two things. Fan that blows in house has a burnt out motor, or the relay that controls both the outdoor unit and the interior fan system is not turning the inside unit. Normal operation is to turn on inside fan and a few seconds the inside turns on. Check to see if the filter has not been sucked into the fan inside causing it to freeze.
  • Alan W Alan W on Jul 11, 2012
    Go to the indoor unit, that is where your problem is. Remove the panels and then manually press the interlocking switch and see if the motor turn. If so the problem is that the squarely gage assembly has come loose from the motor. If the motor does not turn on, then you most liked need a new blower motor. To check it remove the leads from the control board to the motor, and apply 110volt leads to the black and one other color wire. If the motor runs you need a new control board, if not you need a new blower motor.
  • Sandra M Sandra M on Jul 13, 2012
    My outside unit sometimes does not run when even though air is coming through the vents. When I flip the breaker switches off and on a time or 2 the outside unit will then come on. (The breakers are not flipped off, I just turn them off and on myself.) I just replaced the condenser (or compressor??) last summer. I can't tell if I have another a/c problem or whether it is an electrical problem. Can more power be added to the electric box? Sorry the terms not being right...
    • Tam 15076171 Tam 15076171 on Feb 15, 2022

      Yes another breaker should be able to added if your breaker box has enough space for one. Most electricians will give a free estimate

  • Sandra M Sandra M on Jul 13, 2012
    My problem is the opposite! Don't know if I should call a/c guy or electrician.
    • See 1 previous
    • Fonda Hester Goodman Fonda Hester Goodman on Jan 04, 2018

      I am having this issue, it even happens in emergeceny heat. My unit stops kicking on in the inside, the auxilary light even comes on but the fan will not come one. I have gotten it to start by fliping the inside unit breaker off and then on in the past. I dont know what to do, my heat and air guy has been out 3 times, once the capasitor was changed, yesterday the coils cleaned and the other day nothing was found. please help!

  • Ok, if the inside is working and the outside is not there are a few things you can check on your own. The electrical power that feeds the outside unit has either a fuse or disconnect switch. If the fuse blew then you simply need another one. To check that you need to open up the little door where the wires exit on the wall of the house. There should be a little handle there. Pull that out to see if there are fuses on the other side of it. No fuses, simply put it back in the same way it came out. If you look at the handle it may have a off and on logo imprinted on the face. Be sure you can read On and place it in that way. If there are no fuses on the outside, you need to check your breaker panel or fuse panel in the house that feeds the unit. See if the breaker has tripped or the fuse has blown. Reset if it did happen and you should be fine. Change the fuse if it blew. What causes the fuse or breakers to blow is short cycles. If your in an area which the power has gone off and on quickly a lot that will in many cases cause the breaker to trip or fuse to blow. If you ruled out the breaker or fuse, then you need to see if the system is calling for cooling on the outside. Have someone inside the house turn the thermostat up and down. Listen for a click sound on the outside unit. If you have a set back type of thermostat you may need to wait about one min for the sound to happen. If it clicks and the outside unit does not hum or make any noise, then either the unit is low on refrigerant or the run capacitor is burnt out, Both are common issues. in any case a AC person is all that is needed if you ruled out the breaker or fuse.
  • Alan W Alan W on Jul 14, 2012
    if the outside unit is not working. It can be several things. first it can be the 24 volt relay that trips the 230 volt line. To test this, turn the inside thermostat all the way down and go to the outside unit and turn the power off to the unit (breaker box). Open the unit and see if the relay is engaging the 230 volt leads. If you are uncertain then take a wooden object and push down on the ceramic bar that connects the contactors. If it has play, you are not activating the 24 volt relay. To verify this, turn the 230 volts on, and again using a wooden (non conductive object) press on the ceramic bar and see if the unit starts. If so get a new contactor assembly. If it is o.k. then you either have a bad capacitor (the fan should turn slowly ) or a bad fan motor, If when you turn on the unit and it quickly trips the circuit breaker, you most likely have a bad compressor. In either case you should get professional help.
  • Sandra M Sandra M on Jul 14, 2012
    Thank you so much for your help! Sounds like I need to call an A/C pro. August is almost here!
  • Joan Good Joan Good on Jul 21, 2012
    If the outside unit is running but no air is blowing inside, check that the returns aren't blocked, check that the filter is clean, and if that's not it, it's probably the fan or the blower motor (in my case, about a $500 repair) or the control board. If everything inside is working, warm air is blowing, but the unit outside isn't turning on, it may be as simple as a tripped breaker to the AC unit, or as expensive as a dead AC unit. An AC pro is the way to go with that! Sadly, we've had to deal with that as well and it was more expensive, but we were able to get a unit that was a better fit to the size of the house and more energy efficient than the old one that the builder had installed. If you have to replace, ask about rebates from the govt and the power company for installing new equipment!
  • Christel J Christel J on Aug 23, 2012
    that just happened to me and it was the thermostat inside that needed replacing
    • J J on Jul 28, 2018

      That was just said to you so they can sell you a $35 thermostat for $200 i know they did it to me once.. and tried again, but i told them if i am going to pay $200 for a new one i want one that costs $200 not $35... he said well we can out anyone on you want as long as you buy it and pay us $200 to install it.. i lol's and said man if i buy it i am going to install it not pay you to do something a 5 year old can do..

  • Kc Kc on May 20, 2014
    My outside fan is running but theres barely any air coming through the vents...I even places a thermostat on the vent and its registering the temp I have it set on (70*) and its 78* in my house
  • @Kc this can be an issue with the charge in the system. To see if that is the case, go outside and check the pipes that enter into the outdoor condensing unit. If they are iced up you need to turn off the AC system and turn on the fan switch to on position not auto. This will continue to run the blower and assist in melting the ice on the indoor coil that has frozen over thus slowing the air flow to almost nothing if anything at all at the grill openings. Running the fan will also help prevent the ice as it melts from dripping outside of the collection pan inside that would cause water on the floor. Will not prevent this completely, but will help a bit. Check your air filter also. If its plugged and your system is just a bit low on Freon, that may be enough to cause it to freeze over. AC systems need 400 cubic feet of air per ton of air conditioning capacity to properly work. Less air means colder coils that means frozen pipes. If you find the filter is clean, you will need the assistance of a professional to recharge your system.
  • Mike Robbins Mike Robbins on Jun 28, 2014
    I have just purchased a mobile home. The ac unit outside comes on, but I get no air through the vents. Also, there is no air being pulled from the return vent. Im a do-it-yourself kind of person and would like to know what may be causing this problem? You can email me directly at Thanks again!
    • See 1 previous
    • Sharon Taft Sharon Taft on Jul 10, 2020

      I am a few years too late to help, but maybe my answer can help someone else. In 2011 I was living in a trailer with an outside heater/air conditioner combo. We discovered that the vents in the trailer & the heater/air combo were connected with a large tube that was made like a flexible clothes dryer vent. The neighbors cat had gotten under my trailer & put a huge hole in it. Replaced the tube and the problem was solved. All of my cold air had been escaping under the trailer

  • Mike the first thing to try is to switch the thermostat from Auto to On for the fan unit. If the fan does come on and blows air it pretty much tells you that your motor is good and that the problem is with the control circuitry (probably a solid state relay on an older system). Typically most residential units are a single fan system, only commercial units have separate supply and return fans so the fact that you have no return is not of concern, the air handler is not coming on or working. Depending on the system it is also possible that the air handler relay may be low voltage while the relay for the condensing unit (outside) is line voltage so it may be a bad step down transformer that takes the 240 VAC and produces either 24 VAC or even a DC power supply that rectifies and steps down the voltage to 24 VDC. You should be able to trouble shoot these problems with a basic volt meter.
  • PC PC on Aug 02, 2014
    Brian - I have a similar problem if you wouldn't mind helping. The outside unit is turning on and the fan inside starts to push the air through the vents. After about 2 minutes the fan stops and then no air comes out of the vents. The outside unit still continues to run but the blower motor stops.
  • If the fan stops running on the inside. either the blower motor is overheating, Turn off the power on the unit open up the panel that accesses the fan and try to manually rotate the blower wheel. If its stiff the bearings can be worn causing to much friction to the motor. There are devices in some motors that will turn off it is senses overheating. Also the capacitor can be bad on the motor. These $10 parts failing are common. If the blower turns freely, then change the capacitor. You may need a pro for this as these parts are often sold only at establishments that sell to commercial companies only
    • See 1 previous
    • Curtis Haigler Curtis Haigler on Sep 08, 2018

      Or you can get youre units info and search Amazon if it is a capacitor, found mine on there for $20, saved a bunch of $$$👍and it was a fairly simple job to do. Just be careful though, electricity bites

  • Mike Mike on Aug 04, 2014
    i have a similar problem and wanted to make sure i'm on the right track. outside unit is running fine. no air is coming out the vents. i checked the both filters in the wall and in the air handler. checked the breakers. checked and cleaned the float switch. checked the motor to see if it spins fine and it does. i pulled out the variable speed module and don't see any visible damages. should i change the module? please help.
    • Gregg Gerstenberger Gregg Gerstenberger on Aug 28, 2014
      @Mike what ended up being your solution? mine is the same situation. I just had the blower/motor replaced and it started working fine, but now no air comes out of the vents at all and the air handler and outside unit continuously runs.
  • If the fan is not working inside the relay that powers it may be faulty. If the blower is running but your not getting any air, A low AC charge can cause freezing of the coil and blockage of the air flow. Sometimes you just need to power the system down let it sit and then power back up. But in most cases it sounds as though your electronic controls are faulty. Does the board have a light on it? Many do. If it does on the inside of the panel you will see a list of blinking light issues. If there is a window on the air handler, look into it with the system running. count the flashes for a pattern. Then remove the door after turning off the power and compare the flashes with the list. This will tell you what is going on. Does the fan run when switched to fan on mode on the thermostat? If not, the relay is most likely the cause. Very rare for the thermostat being at fault.
  • Mike Mike on Aug 04, 2014
    no visible lights. tried shutting it down and powering it back up. air handler fan looks like it wants to start but spins a bit then stops. fan mode on thermostat is no help. same rumble, fan spins a bit then stops.
  • Relay is dropping out. Also could be faulty transformer. If the VA (volt amps) is not high enough the power is not enough to hold the relay in. But I think you need a new board. What brand is it. Can you provide the model number? Can look up some stuff on this perhaps and shed more light on the subject. Also age is important. If you know. There is a date code normally on the outdoor unit if they match.
  • Mike Mike on Aug 04, 2014
    trane model#TWE037E13FB1. borrowed a friends device to manually operate the fan and it's not running. same scenario, fan starts for a bit then stops. so that eliminates the control board? pulling the fan out to see if there are any visible signs of damage. i found the light, fan light is solid green and cfm light is constant blinking. not sure how to read the blinking light
  • Nick Petrino Nick Petrino on Mar 13, 2015
    im having same issue. the inside unit shuts down but outside fan keeps spinning
  • Wes Wes on Apr 09, 2015
    ANSWER......I'm having the exact same problems. My ac unit is running non stop but no air. The intake wasn't pulling either. I have an hvac guy here and he first thought it was the fan relay but tested the circuit board and it is messed up. Of course the new curcuit board is $450. Hope this helps.
  • Sandy Sandy on May 29, 2015
    Hi Friends, I am facing an issue with our AC unit, during the night when we start the AC it works fine, but later after few hours there is no air coming in the vents but the AC unit is still on and also the blower/fan is running, I can hear the sound, hwat troubleshooting steps i can do to isolate the issue? Thank you for your time, -Sandy
  • Betty Gramse Betty Gramse on Jun 25, 2015
    Mine was doing something similar. The fan was running but not cooling. My son came by and noticed it was almost 80 in the house and went to the breaker box and flipped on the switch for the AC.
  • Tonia Michelle Powers Tonia Michelle Powers on Aug 01, 2015
    My fans turn but no air is coming through intake the coils are getting cold the heat doesn't work in winter
  • Betty baldwin Betty baldwin on May 30, 2017

    I had a new furnace installed last fall. Then we noticed the fan on the outdoor a/c unit was running. We shut the outdoor breaker off for the winter. We just tried turning on the A/C and it works but when we switched it off at the thermostate the fan out side started running on its own again. Do you know what could cause this Thanks Betty

  • Dan23809782 Dan23809782 on May 30, 2017

    Have you cleaned or changed or air filter.

  • User User on May 31, 2017

    When i turn my ac on i can hear it come on but no air come out whats the problem?

    A lil bit air comes out

    • Vernon Vernon on Jul 18, 2018

      I have the same issue. outside unit on. blowers on inside are on but no air through vents. 95 degrees in my home. Please help. I have a 2 yr old and she is miserable in this Texas heat.

  • User User on May 31, 2017

    Only a lil bit air is coming thru the vent i dont why its doing that

  • Tima Tima on Jun 02, 2017

    My ac compressor outside is pushing out our air and it's not coming into the apartment ?

  • Rob25103951 Rob25103951 on Jun 12, 2017

    I have an odd issue. My compressor is running and I can hear / feel air being pulled into the return, but no air is coming out of the supply vents. Any suggestions?

  • Annie Annie on Jun 14, 2017

    I don't have a inside unit

  • Felicia Bracamontes Felicia Bracamontes on Jul 14, 2017

    My unit is working just a dirt a little cool air was coming through then all of sudden no air at all is coming thro we just changed filters and it was working fine but then this happened

  • Karen Brock Karen Brock on Jul 14, 2017

    Sorry, your fan motor might be in need of replacement. In central Florida it's about $350 I think.

  • Gee28884595 Gee28884595 on Aug 07, 2017

    Ok, I have read and read and have not come upon my problem (and common sense says it ain't so). The entire unit is working fine.....except no air comes out of the vent. The filter is new, I have no duct dampeners and condensate tray is fine. It's like it's being blocked somehow but before I start tearing the duct system apart, any ideas? It was fine 2 hours ago. The unit I have, the heater portion sits on top of the cooling. I say the blower is working fine because there is air moving in the open compartment. I can not see the actual blade or motor spinning as this is a very small area to work in. HELP!!!

    • Gee28884595 Gee28884595 on Aug 07, 2017

      Ok, I put a camera in the unit and the blower is working fine and since the air is forced through the coil and out, I must have a problem with the coil. Now since that's a sealed unit, I can only suspect that the unit is frozen pretty solid and not allowing air to get through. I am going to let the unit sit for about 2 hours and see if it defrost. (Sometimes, just talking this through by myself, I can figure things out.)

  • Stevie Jones Stevie Jones on Aug 12, 2017

    When i turn on my ac no air comes through but the outside unit is runningi dont know what the problem is. Please help me

  • Tiffany kline Tiffany kline on Sep 03, 2017

    How would i know if my air froze up

  • Jennifer Baker Jennifer Baker on Jul 07, 2018

    Our a.c. turns on just fine but when air starts to blow inside it's Super a loud fan/air blowing. Filter is ok.... help!!!

  • Lakesha Lakesha on Jul 14, 2018

    Do u have to have air filter so your air can work

  • Toi Toi on Oct 03, 2018

    My outside unit runs, the air handler is in attic (zone 2), zone 1 is fine. The fan does run, the termostat is fine. Can the overflow switch cause the air handler to NOT blow air, but the fan still works?

    • Toi Toi on Oct 03, 2018

      I'm trying to see if the overflow is activated due to water build up, would the fan be affected too. I feel slight air and hear the fan running, but when I switch to cool/heat, no air flows.

  • Ryan Ryan on Jul 25, 2019

    This thread has been going a long time but continues to receive regular updates and inquiries so it must be a fairly common issue.

    Here's what I am experiencing: I live in central CA, summer temps routinely get to 105 and sometimes even 110, but very little humidity. The unit is a 30 year old roof mount central heat and air system, original to the house (not sure of brand). The house is about 1,600 sqft, approximately 1/2 of which has 12' vaulted ceilings.

    The unit will act like it's going to turn on, but the fan never kicks on and no air comes from the vents. I checked the return vent, okay, filter a little dusty but not too bad. I replace filter, vacuum off register vent grate and try again.

    Same response. Turned unit off for several hours (from about 4:30 PM to 10:00 PM) thinking maybe iced up coils. It was 103 and the unit sits in the sun all day long. Left the unit off overnight (10:00 PM to 4:30 AM), it didn't get below 75 overnight (I'm mentioning temps and times because I believe I allowed adequate time for the coils to de-ice before trying again), and the problem still persists today.

    One thing that I did notice is that I do get some weak airflow coming OUT of the return vent, very cold air. If I left it on long enough, it would lower the thermostat temperature a few degrees since the thermostat is located almost directly under the return vent.

    An AC company came out and performed extensive maintenance last year. Apparently there was extensive air leaks around the unit and a few parts needed replaced. They also performed a routing cleaning and whatnot.

    What're your thoughts? Time to replace the unit?

    I have noticed the past couple months when the unit runs, water drips from it, runs down the roof and into the rain gutters. It eventually reaches the downspout with sufficient enough volume to create a small puddle at the bottom of the down spout, if that matters or helps at all.

    • Alisa Poole Lopez Alisa Poole Lopez on Sep 01, 2019

      Lemme know if you get a response, please. Damn near same issues here. Gonna be a long hot miserable labor day weekend in Corcoran. 😩

  • Colleen Smith Colleen Smith on Aug 11, 2019

    My home AC unit stopped blowing cause it froze up. We defrosted it,but it froze up again. My friend said it wasn't defrosted long enough so we did it for about 8hrs and then we put the panel on and it wouldn't blow cold air. It will however blow air, not really cold air but some only with the panel off.....side note we did have to clean the coils which we did but still didn't really help. Any answers

  • Car48061903 Car48061903 on Sep 15, 2019

    I came to this site with no air coming from vents. Fan is running. I opened the door to my inside unit and felt air coming through the door. That is not right! I located a hole in duct work. Going to see if I can repair in the morning.

    • DebWor DebWor on Dec 09, 2019

      My until does this is the tray inside fills with water. Check out side. See if water is dripping out of the pipe coming from the house? If not take a water vacuum and hold it there. It should start to pull out alot of water. You can also go to where your indoor unit is vacuum out the tray. Do not crack the tray about$600. to replace. So I just let the vacuum do the work. Sometimes small piece of insulation gets in mine. Its in the attic. I hope this works Good Luck

  • Joe Joe on Apr 21, 2020

    My air kicks on and everything works fine. It gets down to the right temperature and cuts off as it should. When the unit turns back on, only the outside unit comes back on, the inside does not. I replaced the capacitor on the inside fan blower motor. Still nothing. If I let it sit a few hours, the whole thing works again! Frustrating!

    • See 2 previous
    • Casey Langford Casey Langford on Jun 04, 2020

      Repair man came back today and stated it was the circuit relay board. I’m guessing it’s the same thing as your issue. So over it all! Thanks for the info and responding.

  • Ernie Ernie on Jul 31, 2020

    my ac fan blower work for 7to 10 hours then stop then i will wait 2 hour to start it up again. any guest what it could b

  • MELISSA MELISSA on Aug 28, 2020

    My a.c. unit is running but not pushing any air at all!! Any suggestions..

  • So if the compressor turns on the thermostat is working. If the air is not moving it's a problem with the blower. Either the motor has burned out or there's an electrical problem - a bad relay or circuit breaker - that is stopping power to the blower.

  • Saying that no air is moving leads me to believe it's a problem with the fan or blower. The motor may be seized.

  • Chloe Crabtree Chloe Crabtree on Jun 16, 2021

    This sounds like the inside fan or the inside blower is not working. I am sorry, but it sounds like you are going to need that service call.

  • Annie Annie on Jun 16, 2021

    I agree with Ann, it sounds like a fan problem. Get the service call and try to keep an eye on what the tech does to fix the problem. But maybe you need new parts?

  • We had a similar problem when we first moved in; the outdoor unit wasn't connected to the indoor unit. If you've had cool air before, that might not be the issue but it does sound like you should call a pro rather than tinker with it if you don't know how these things work. You could easily accidentally do a load of damage.

    Bit of advice -- have more than one company come out to take a look. We got duped by a company for something we didn't need that also didn't fix the issue. A second more reputable company informed us and fixed both problems for far less.

  • Deb K Deb K on Aug 02, 2021

    Hi Scott, if you have not diagnosed this yet, Condenser Unit is Blocked If your air conditioner is running, but not lowering temperatures inside, one issue could be a blocked or clogged condenser coil. When operating correctly, the condenser fan draws air into the outdoor unit through the condenser coil to pull heat energy out of your home.

  • Courtney Courtney on May 21, 2022

    Check your trunk line

  • Toni Toni on Jul 25, 2022

    Hi Scott, have a question to ask u .My A/C is working outside and inside and there is some cold air coming through vents but not like it usually does. I have changed the filter the other day and it still is not better. I can feel the real cold air if I put my hand to the vent and but it's like it is not being fully being pushed out . I thought maybe blower motor. Do u have suggestions on this please. Thank you so much for ur help .

    • Maurice Glenn Maurice Glenn on Jul 16, 2023

      Outside unit running but inside blower not best case hopefully and more likely the Capacitor I'm an apartment Maintenance Tech I've replaced many of them Capacitor is like a battery 5 minute replacement Silver looking battery with prongs that has 3 wires hooked to it

  • Toni Toni on Jul 25, 2022

    My bad not Scott.

  • Michael Sun Michael Sun on Jan 10, 2023

    One possible reason for this problem is that there may be an issue with the blower motor or the fan that is responsible for moving the air through the system.

    If the motor is faulty or the fan is not spinning, then the unit will not be able to blow air.

    In addition, it is possible that the thermostat is faulty, and it is not sending the correct signal to the air conditioning unit to turn on the fan.

    A problem with the ductwork is also possible that it can be leaky and not properly insulated, which can lead to air loss and poor airflow.

  • DAme DAme on Jan 12, 2023

    The reasons why the air conditioner does not cool the room - sorting from the most common reasons to the rarer ones.

    The indoor unit filter is clogged with dust. In this case, a dirty air conditioner filter does not allow air to pass through. Air does not pass - it means it does not cool;

    The winding of the fan of the indoor unit burned out. The blades don't rotate fast enough for the air to take all the cold away from the radiator;

    Compressor start capacitor burnt out. In this case, the external unit does not start. In this case, the indoor unit works as a fan - the air conditioner works, but does not cool;

    There is no freon in the system. As a result of the leak, a shortage of freon was formed. Out of ten calls for repairs, there is only one refueling;

    Air conditioner refilled with freon. Increased freon pressure as a result of a refueling error;

    The outdoor unit is protected against overheating. For example, it can be clogged with dust, feathers or poplar fluff, or it can be installed on a closed balcony. Due to insufficient circulation of fresh air around it, the unit will overheat and turn off.

  • Marcella moore Marcella moore on Jul 20, 2023

    My AC unit outside is running but no air is blowing in my vents

  • Johnavallance82 Johnavallance82 on Jul 21, 2023

    Sounds as if a filter is clogged up!

  • Elizabeth Elizabeth on Aug 21, 2023

    My house was super cold and AC was working wonderfully. Then, next day nothing. I changed the filters, cleaned the outside unit, followed reset instructions. Turned it back on and the fan wouldn't turn. I took a metal file and turned it. It immediately started spinning fast and air started coming through. About 30 minutes later it stopped again. The unit outside. What are my options? The unit isn't old. The repair guys charge us an arm and a leg to only reset it.