Outside fan not turning on ac unit

Is your AC fan not working? Or, perhaps you’re not even sure if it’s the fan that’s causing your AC problems.

Either way, you’re in the right place to find the answers you need. Below is a list of common AC fan problems and how to fix them. Using this checklist, you should be able to check for/diagnose the symptoms of your malfunctioning AC fan.

Simply follow these AC fan troubleshooting steps to get your cold air flowing again ASAP.

Scenario 1: Fan Isn’t Spinning and You Can’t Hear the Compressor

First, turn on your air conditioning, head out to the compressor unit outside your home, and listen. Even if the fan isn’t working, you should still hear the hum of the compressor.

If you hear nothing, the fan isn’t the problem. Your compressor isn’t receiving any electricity. This could be a circuit breaker issue or a faulty contactor.

Solution 1

First, go inside and turn off the AC. Then, go check the circuit breaker. The switch you’re looking for should say something like “HVAC,” “furnace,” “AC,” or “compressor.”

If the switch is turned off, try turning the switch back on, and go inside and try the AC again. If the switch is already on when you check it, turn it off, wait a few seconds, then turn it back on again and try the AC.

Go out and listen to the compressor. If you still hear nothing, it’s probably a contactor issue. Proceed to Solution 2.

Solution 2

The contactor regulates the power flow to your compressor unit. If it’s malfunctioning, this explains why your compressor isn’t getting power.

The only way to be sure that this is the problem is to check the contactor’s voltage. This is not a job for novices. Unless you’re an experienced HVAC professional, call someone who is to take a look at your system.

Scenario 2: Compressor is Working But Fan Still Isn’t Spinning at All

If you do hear the compressor humming but the fan isn’t spinning at all, it’s most likely a bad capacitor to blame. The capacitor is what starts the fan moving.

You see, the fan doesn’t require much energy once it’s running. But starting the fan takes a big jolt of energy. The capacitor keeps this energy stored up like a battery until it uses it to start the fan.

Solution 3

To test if the capacitor’s the problem, try to “kick-start” the fan. You’ll need a long stick of wood or other non-conductive material to fit through the fan grate.

First, though, make sure the AC is turned on and set to be running. Then, use the stick to try and push the fan hard enough to give it a good spin.

This should be enough to start the fan moving if, in fact, it is the capacitor causing the problem. If it starts this way, call an HVAC technician to replace your capacitor.

If the fan doesn’t start no matter how hard you spin it, the problem must be something else. Continue to Solution 4.

Solution 4

If the fan won’t start even with a kick-start, and you hear the compressor running, you probably have a bad fan motor. This is more common with systems that are poorly maintained or that operate where a lot of dirt/debris is blown around by the wind.

The only thing you can do about a bad motor is to have it replaced. This is expensive, though, so make sure you check all other options on this list first.

Then, have a trustworthy HVAC technician take a look at it to make sure this is the problem. Also, if your HVAC is over 10 years old, it might be better to replace the whole thing.

Scenario 3: The Fan Spins Slowly

The next scenario is when your fan spins slowly. You may notice this symptom when your system is running or when you attempt to kick-start the fan.

Solution 5

The simplest solution in this scenario is to check your air filter. Unfortunately, many homeowners and tenants are unaware that they are supposed to check this regularly.

An air filter that’s filled to capacity is basically a clog in the airflow of your system. This puts strain on the fan, which can cause it to run slowly or burn out.

If you don’t know how to check the air filter, click here for instructions. If this isn’t the problem, proceed to Solution 6.

Scenario 4: The Fan Spins Slowly and Loudly

The next scenario is when your fan makes a loud noise like it’s grinding against something while it spins slowly. Again, you may notice this when you attempt to kick-start the fan. This probably means the fan is blocked by debris or another component.

Solution 6

Turn off the AC from the thermostat and the circuit breaker. Check the fan for any debris or components it is contacting while spinning. Using your kick-start stick to manually spin the fan makes this easier.

If you notice any debris, clear it out, turn everything back on, and listen to it again while it’s running. But, if this doesn’t solve the problem, or you can tell the fan’s contacting another component, call an HVAC professional to repair it.

Scenario 5: The Fan/System Turns On and Off Randomly

Does your fan or system keeps turning on or off at random times, regardless of your thermostat settings? You may even hear the electrical clicking noise of the system turning on and off, on and off.

Solution 7

This is almost definitely an issue with the wiring, the control board, or some other electrical component of the system. Call an HVAC repair technician to fully diagnose and fix the problem.

How do I reset my outside air conditioner fan?

Why is central air fan outside not working?

Is the outside fan supposed to run when the AC is on?