Common Reasons Air Conditioners Won't Turn On

Updated: May 18

AC Won't Turn On—Don't Lose Your Cool


AC Wont Turn On - Reason Air Conditioners wont turn on

Find out how to address these commonly experienced air conditioner issues and what to do when the AC won't turn on.




Why Won't My Air Conditioning Turn On?

Always turn off the power when touching or disassembling any part of a condenser unit—or risk electrocution!


Thermostat Issues

Try turning on a thermostat with a blank display. If that doesn't work, check to see if it requires batteries, and change them. A diagnosis by an AC professional is a final option.


Tripped Circuit Breaker

A tripped circuit breaker is a common cause of powerless AC systems. Restore tripped breakers in the electrical panel to their "ON" position. Breakers that trip repeatedly, pose a danger and require professional service; never force the breaker on as it is doing its job by kicking off.


Unplugged Condenser Unit

Visually check that power cords to condenser units are plugged in, undamaged, and in working order.


Blown Fuse

Fuse boxes are usually located outside, near the condenser unit of central AC systems. After turning off the power, a visual or electrical test, covered with Learning about Electronics, can determine if any fuses have blown—a service routinely performed by AC service professionals.


Clogged Air Filter

Clogged air filters cause evaporator coils to freeze, ice to form, and ACs to stop operating. After turning off the power, changing the filter, and allowing ice to melt, an AC unit should turn on again. If not, a professional tune-up is recommended.


Clogged AC Drain Line

AC condensation drain lines are cleared and maintained by turning off the power and pouring boiling water down them once each month.


AC Motor Failure

Motor failure is common with unmaintained AC systems more than five years old.


Refrigerant Leak

AC units usually stop cooling or make unusual sounds before they stop operating altogether as a result of a refrigerant leak—a dangerous situation, as featured with WebMD, that requires an AC professional be contacted.


False Temperature Readings

The temperature at the thermostat, as explained with Reviewed, determines when the AC operates. Too hot, near a dryer or in a sunny location, and it causes the AC to operate too often. Too cold, and vice versa. Relocating the thermostat is the simplest—and best—solution.


Deluxe Plumbing & Heating provides professional AC maintenance for all makes and models. Call us, we'll determine why your AC won't turn on and get it running properly again.