San Antonio · AC Contactor Repair · Family-Owned Since 2010
A contactor is the relay switch that tells your outdoor unit when to run. When the contacts pit and burn — and they always do, eventually — your AC either won't start or won't shut off. Most jobs done in 45 minutes.
Typical price
$185–$320 installed
Time to fix
30–60 minutes
Urgency
High — risk of compressor damage
The contactor is a small black box inside your outdoor disconnect that physically closes a circuit every time your thermostat calls for cooling. It's basically a heavy-duty light switch that flips on and off thousands of times every summer.
Every time those metal contacts open and close they create a tiny arc. Over 4 to 6 San Antonio summers, that arcing pits and burns the contact surfaces until they either weld shut (AC runs nonstop) or won't make contact at all (AC won't start, even though the thermostat is calling).
The contactor and capacitor sit right next to each other inside the disconnect box. When one fails, the other is usually right behind it — we'll always test both while we're in there.
What it costs in San Antonio
$185–$320 installed — Includes a quality 30-amp or 40-amp contactor, labor, and a full electrical check. Diagnostic is free and the written price comes before any work — you only pay if you green-light the fix.
Unexpected HVAC repairs can be stressful. Flexible repair payment options may be available to help keep your home comfortable without the financial pressure.
If two or more of these sound familiar, it's probably your ac contactor.
Here's exactly what a Carnes and Sons tech does at your house — no mystery, no upselling.
We pull the disconnect, open the access panel, and look at the contact surfaces. Pitted, blackened, or welded contacts are an automatic replace — they won't get better.
With the meter we check that the 24V control voltage is reaching the coil correctly and that the closed contacts read less than 0.5 ohms. Anything higher means heat and impending failure.
We size up to a 40-amp Mars or Packard contactor for longevity. The extra capacity costs about $8 wholesale and easily doubles the life. We seal the disconnect box against ants while we're in there.
Re-energize, watch a full cool cycle, measure inrush and running amps on the compressor, and make sure the contactor pulls in clean and crisp. Then we show you the old burned part.
Get Your AC Contactor Diagnosed Today
Tell us what's happening. We'll text you back in minutes — no call center, no robo-calls.
$185 to $320 installed, depending on the amp rating (30A or 40A) and whether the disconnect box needs cleaning or the wire lugs need repair. Service calls are free — we limit to 6 per day to keep response times fast.
The capacitor stores electricity and kicks the motors into starting. The contactor is the switch that connects high voltage to those motors when the thermostat calls. They sit side-by-side in your outdoor unit. Both wear out, often within a year or two of each other.
Almost always a contactor with the contacts welded shut from arcing. The thermostat is telling the unit to stop, but the switch is physically stuck closed. Cut power at the disconnect or breaker right away — running the compressor nonstop will burn it out in a day or two.
Yes — and they do, constantly in San Antonio. Crazy ants are attracted to the electrical fields in the disconnect, get crushed between the contacts, and short out the unit. We seal the box and treat around the slab as part of every contactor job.
A factory 30A contactor lasts 4 to 6 summers in San Antonio. A 40A upgrade lasts 8 to 10. Annual maintenance and keeping ants out adds years.
If both are 4+ years old, yes — we strongly recommend it. The combined job adds about $80 and you save a second service call later. We'll always show you the readings on both before recommending.
Yes. Contactor calls are a daily occurrence for us in summer — we keep same-day slots open. Text (210) 600-5091.
5 years on the contactor itself, 1 year labor. If the new contactor fails inside 5 years, we replace it free.
We're based in Stone Oak and roll trucks across San Antonio and the surrounding Hill Country every day.
License TACLB29435E · Family-Owned Since 2010
Cities & neighborhoods we serve
San Antonio · Stone Oak · Alamo Heights · Hollywood Park · Hill Country Village · Shavano Park · Castle Hills · Leon Valley · Helotes · Boerne · Fair Oaks Ranch · Bulverde · Timberwood Park · Garden Ridge · Schertz · Cibolo · Selma · Universal City · Live Oak · Converse · Windcrest · New Braunfels
No call center. The owner or one of his sons picks up.
(210) 600-5091