Inside Fan Running but Outside AC Unit Not Working? Here Is Why

If you can feel air coming out of your vents but it is not cold, walk outside and listen. If the outdoor unit (the condenser) is silent or just humming, that tells us a lot about the problem.

Things you can check safely

The outdoor disconnect. Make sure the disconnect box on the wall next to the unit is switched on or the pull out block is fully inserted.

The breaker. Your outdoor unit usually has its own breaker in the panel, separate from the indoor unit. If it is tripped, reset it once. If it trips again, stop and call a technician.

The thermostat. Make sure it is set to COOL and below room temperature.

A safety switch. Some systems shut down the outdoor unit when the condensate drain is backed up or when high pressure is detected. A dirty outdoor coil on a hot day can trigger a high pressure shutdown.

Common repairs we find

Bad capacitor. This is one of the most common summer repairs. The capacitor gives the compressor and fan motor the boost they need to start. A failed capacitor often causes a humming sound with the fan not spinning. Capacitors store a dangerous charge, so please do not open the unit.

Failed contactor. The contactor is the switch that tells the outdoor unit to turn on. They wear out, get pitted, and can be blocked by ants or insects.

Fan motor failure. If you hear the compressor running but the fan on top is not turning, shut the system off right away. The compressor can overheat without the fan.

Wiring or low voltage problems. Chewed wires, a blown fuse, or a bad control board can keep the outdoor unit from getting the signal to start.

Turn it off until it is fixed

Running the indoor fan without the outdoor unit just moves warm air around and can lead to a frozen coil once the outdoor unit kicks back on. Turn the system off and call for service.

Red Rock Mechanical carries common parts on our trucks so we can fix many of these issues on the first visit. Call (405) 305-3085 or book online.