AC won’t turn on · Pueblo, CO
AC won’t turn on
Thermostat set, nothing happening. Run through the checks below — if the system still won’t start, call us and we’ll send a technician.
- Answering calls 24/7
- Licensed & insured technicians
- Pueblo & Pueblo West, ZIPs 81001–81012
Work from the thermostat outward
Power and the signal to cool travel from the thermostat to the indoor unit to the outdoor unit. Check them in that order.
- Thermostat. Display on? Replace the batteries if it has them. Mode on Cool, setpoint a few degrees below room temperature. Then wait about five minutes — most thermostats hold the compressor off for 3–5 minutes to protect it.
- Indoor switch. Many furnaces and air handlers have a switch nearby that looks like a light switch. Make sure it’s on.
- Breakers. In the main panel, look for tripped breakers marked AC, condenser, furnace or air handler. Reset once.
- Outdoor disconnect. The gray box on the wall beside the outdoor unit. Some have a lever, some a pull-out block. A pulled or switched-off disconnect is one of the most common reasons an AC won’t run.
- Drain pan and float switch. If there’s standing water in the pan under the indoor coil, a safety switch may have shut the system down on purpose.
The parts that usually fail
| Capacitor | Gives the compressor and fan motor the jolt they need to start. When it fails, the outdoor unit may hum without starting, or start and stall. Running on a bad capacitor can ruin the compressor. |
|---|---|
| Contactor | An electrical switch inside the outdoor unit that sends power to the compressor and fan when the thermostat calls. Arcing pits its contacts over time; insects and debris can jam it open — or stuck closed, so the unit won’t shut off. |
| Float switch | Cuts the system off when condensate backs up. It’s doing its job; the real problem is the clogged drain. |
| Thermostat or control wiring | A dead thermostat or a loose low-voltage wire breaks the call for cooling before it reaches the outdoor unit. |
| Compressor or fan motor | Hard starting, loud clicking at startup and repeated breaker trips can all point here. |
All of these involve live electrical parts. Our technicians test them with the right meters and tell you what failed before replacing anything.
Typical U.S. range for fixing a faulty contactor: $150–$400, per Fixr, August 2026 — a national figure, not a Pueblo quote. Your exact price comes after diagnosis.
Power outages and shutoffs in Pueblo
If nothing in the house works, the AC isn’t the problem. Black Hills Energy, the electric utility in the city of Pueblo, can cut power to some areas under its Public Safety Power Shutoff program during extreme wind and fire danger. Check for an outage with your utility first — in Pueblo West, that may be Black Hills or San Isabel Electric depending on which side of Highway 50 you’re on.
When power comes back, wait five minutes and make sure the thermostat is still on Cool. If the AC breaker tripped while the power was out or the outdoor unit hums and won’t start, call us.
Smell something burning?
Burning smell, smoke or sparks at the unit? Cut the power first.
Turn the system off at the thermostat, then switch off the air conditioner’s breaker in your electrical panel. Don’t open the outdoor unit: its capacitor can hold a dangerous charge even with the power off. If you see flames or smoke that keeps coming, get everyone out and call 911. Once the power is off and everyone is safe, call us.
Questions we hear
The breaker keeps tripping. Can I just keep resetting it?
No. One reset is reasonable. If it trips again, something in the system is drawing too much current — a shorted wire, a failing compressor or fan motor — and repeated resets can make the damage worse. Leave the breaker off and call us.
The whole neighborhood lost power and now the AC won’t start. Why?
Give it a few minutes after power returns: many thermostats wait 3–5 minutes before restarting the compressor. Some thermostats also lose their settings, so check that it’s back on Cool. If the breaker tripped during the outage or the outdoor unit hums without starting, call us.
There’s water in a pan under the indoor unit and the AC is dead. Related?
Very likely. Many systems have a float switch that cuts power to the AC when condensate water backs up, so the house doesn’t flood. Clear the clog and it usually resets. See AC leaking water.
Sources
- Fixr — AC Repair Cost: Common Issues & When to Replace (2026) (August 2026)
- Carrier — AC unit not turning on
- Lennox — Outdoor AC unit not turning on
- Lennox — Why your air conditioner won’t turn off
- Bryant — “Cool On” flashing on thermostat
- Bryant — AC fan not spinning or turning on
- Bryant — AC capacitor replacement
- Bryant — How to repair and troubleshoot your AC
- Trane — Air handler overflow switch
- City of Pueblo — Online Payments (utility providers)
- Pueblo West Metropolitan District — Local Utilities
- Black Hills Energy — Colorado Emergency Public Safety Power Shutoff