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AC Won't Turn On
in Lewisville, TX
When your AC won't turn on at all, it's a short list of things to check. Some of it you can check yourself, like the breaker. But parts inside the outdoor unit — especially the capacitor — require a technician. In Lewisville's heat, don't wait more than a few hours to figure out which it is.
Quick Answer
If your AC won't start in Lewisville, the most common causes are a tripped breaker, a bad capacitor in the outdoor unit, or a thermostat that's lost power or failed. A capacitor is a small cylindrical part that helps the motors start — they fail often on units more than 5 years old. Call (361) 401-8806 and a technician can usually tell you over the phone whether to check the breaker first.
Telltale Signs
Warning Signs to Watch For
- The thermostat is set lower than room temperature but nothing happens
- The outdoor unit is completely silent — no hum, no fan
- The indoor unit doesn't blow any air
- The circuit breaker for the AC has tripped to the middle position
- The thermostat screen is blank or unresponsive
Root Causes
What Causes AC Won't Turn On?
Failed Start Capacitor
The capacitor gives the compressor and fan motors the extra push they need to start. When it fails — which happens frequently on units that have run through more than 5 Lewisville summers — the motors can't start even though power is reaching the unit. You might hear a single hum or click, then silence.
The Fix
Capacitor Replacement
A technician discharges the old capacitor safely, removes it, and installs a new one matched to the system's specs. It's one of the faster fixes in AC repair, and the new part should last several years.
Tripped Breaker or Blown Fuse
A power surge — like the ones that come with the strong thunderstorms that roll through Lewisville from March through May — can trip the AC breaker or blow a disconnect fuse at the outdoor unit. The system won't start at all until power is restored. A breaker that keeps tripping after you reset it means there's a deeper electrical problem.
The Fix
Breaker Reset or Fuse Replacement
If the breaker holds after a single reset, you're probably fine. If it trips again, a technician needs to find out why — it's usually a failing compressor or a wiring issue drawing too much current.
Thermostat Failure or Dead Batteries
A thermostat that loses power can't send a signal to the AC to start. This is more common than people expect, especially with older battery-powered thermostats in homes built in the 1990s in places like Old Town Lewisville. A blank screen or unresponsive thermostat is the first thing to check before calling anyone.
The Fix
Thermostat Replacement or Battery Swap
Replace the batteries first — it takes two minutes and fixes the problem more often than you'd think. If the thermostat still doesn't respond with fresh batteries, the unit itself has likely failed and needs to be replaced.
Self-Diagnosis
Which Cause Applies to You?
Check the signs you're observing to narrow down the likely root cause before your inspection.
| What You're Seeing | Failed Start Capacitor | Tripped Breaker or Blown Fuse | Thermostat Failure or Dead Batteries |
|---|---|---|---|
| Outdoor unit hums once then goes silent | |||
| Breaker for AC is tripped at the panel | |||
| Thermostat screen is blank or shows no display | |||
| No response from system at all — no sound, no airflow | |||
| Breaker trips again immediately after reset |
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