AC & heater troubleshooter · Surprise & West Valley

What’s Wrong With My AC or Heater?

Pick what’s happening, try a few safe checks that often fix it, and know exactly when it’s time to call a technician.

What’s happening?

Pick the closest match to see safe things to check before you call.

Cooling

Heating

Troubleshooting questions

Why is my AC blowing warm air?

The most common causes are a thermostat set wrong, a clogged filter, a tripped breaker, or a failed capacitor that stops the outdoor fan or compressor from starting. Check the thermostat, filter and breakers first. If the outdoor fan isn’t spinning or a breaker trips again, call a technician.

Why won’t my AC turn on?

Check that the thermostat has power and is set to COOL, replace its batteries, check the breakers and the power switch by the indoor unit, and look for a backed-up condensate line that can trip a safety switch. If it still won’t start, call for service.

Why is my heater blowing cold air?

Often the thermostat fan is set to ON instead of AUTO, the heat pump is in a normal defrost cycle, the filter is clogged, or a breaker has tripped. If it’s still blowing cold after 10–15 minutes, call for service.

When should I stop troubleshooting and call?

Call right away if a breaker trips again after one reset, you smell burning, you see ice on the lines, or the outdoor fan hums but won’t spin. If you smell gas, leave the home and call Southwest Gas or 911 from outside.

Thinking the system may be done? Try our repair or replace calculator.