How much does a furnace control board cost?
$385 to $795 installed in San Antonio. The board itself is $150–$450 depending on brand and age — common Carrier/Trane/Goodman boards are cheap; proprietary high-end and older boards are expensive.
San Antonio · Furnace Control Board Replacement Repair · Family-Owned Since 1996
The Little Green Board Inside Your Furnace Just Died. Here's What Replacement Costs.
The integrated control board (or 'IFC') is the brain of your indoor unit. When it goes bad, nothing runs predictably — random no-heat, no-cool, blower stuck on, ignition failures.
Typical price
$385–$795
Time to fix
60–90 minutes
Urgency
High — usually means heat or cooling is completely out
In plain English — what's going on with your furnace control board replacement
Inside the cabinet of every modern furnace and air handler is a circuit board roughly the size of a paperback book. It runs everything — when the blower starts, when the gas valve opens, when the ignitor fires, what the LED error codes mean. When this board fails, the symptoms can look like a hundred different problems.
The most common failure mode in San Antonio is surge damage from CPS Energy grid hits during summer storms — capacitors blow, relays weld, traces burn. Less common is heat damage from a clogged filter overheating the cabinet over years.
Replacement is straightforward when you have the right board — but boards are model-specific and can be expensive ($150–$450 for the part alone). $385 to $795 total installed. We carry universal boards for common brands and can usually fix same-day.
What it costs in San Antonio
$385–$795 — Wide range because boards vary from $150 (common brands) to $450+ (proprietary or older models). Our $59 diagnostic is waived when you approve the repair, so you only pay for the fix itself.
Symptoms you'll notice at home
If two or more of these sound familiar, it's probably your furnace control board replacement.
Furnace or AC completely dead, no LED activity inside the cabinet
Random LED error codes flashing on the board
Blower runs constantly and won't shut off
Ignition won't fire even though gas and ignitor are good
AC contactor won't pull in even with 24V signal
System worked fine, then quit after a thunderstorm or power flicker
Why furnace control board replacements fail in San Antonio
- Voltage surge from CPS Energy grid hits or summer storms.
- Failed transformer pushing wrong voltage to the board.
- Mice chewing on wires or nesting on the board (yes, really common).
- Heat damage from a clogged filter overheating the cabinet.
- Water damage from a leaking coil or overflowed drain pan above the cabinet.
How we diagnose and replace it
Here's exactly what a Carnes and Sons tech does at your house — no mystery, no upselling.
- 1
Read the error code on the board
Most boards flash an LED diagnostic code. We read it (every brand is different) and use the manufacturer's chart to narrow the failure mode.
- 2
Verify incoming power
Check the 120V at the board, the 24V at the transformer secondary, and the fuse on the board itself. Sometimes a $4 fuse fixes it.
- 3
Test board outputs under load
We jumper the thermostat connections to call for cool/heat/fan and verify each output. If outputs don't fire when they should, the board is bad.
- 4
Install matched replacement and verify operation
Match the board by model or use a universal cross-reference. Reset the dip switches/jumpers to match your system, install, test every mode (cool, heat, fan only).
What Your Neighbors Are Saying
Get Your Furnace Control Board Replacement Diagnosed Today
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Furnace Control Board Replacement questions San Antonio homeowners actually ask
How do I know if the control board is bad?
Flashing LED error codes inside the cabinet, system completely dead, or random behavior (blower stuck on, ignition failures, contactor not pulling in). A real tech reads the diagnostic LED and tests outputs with a meter — guessing is expensive.
Can I replace it myself?
If you're comfortable with low-voltage wiring and can match a board, possibly. Risks: wrong board for your model, incorrect dip switch settings, missing a wire (10+ low-voltage connections), creating a fire hazard. We've fixed a lot of DIY board attempts that ended up costing more than calling us.
Why does my board keep failing?
Usually unprotected power. CPS Energy surges and summer lightning take out boards every year. A $385 whole-home or unit-level surge protector pays for itself the first time it saves a $700 board.
Will a universal board work?
For most common brands yes — we carry universal boards that cross-reference to Carrier, Trane, Goodman, Lennox, Rheem. Some proprietary boards (older Lennox, some high-end variable-speed) require OEM only.
Is the board warrantied?
Parts are 1–5 years depending on brand and whether your system is still under manufacturer warranty. We always check warranty status before quoting.
Can a power surge cause this?
Absolutely — most common cause in San Antonio. Lightning hits, transformer flicker, even your fridge cycling on a weak grid can spike enough to fry a board. We strongly recommend a surge protector after a board replacement.
How long will the new board last?
10–15 years with surge protection. 3–7 years without, in San Antonio's storm-heavy summers. Worth the $385 surge protector.
Serving furnace control board replacement repairs across the greater San Antonio area
We're based in Stone Oak and roll trucks across San Antonio and the surrounding Hill Country every day.
Carnes and Sons Air Conditioning
License TACLB29435E · Family-Owned Since 1996
401 E Sonterra Blvd Suite 375
San Antonio, TX 78258(210) 600-5091
San Antonio, TX 78258(210) 600-5091
Mon–Sat: 7AM – 8PM · Emergency same-day service
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
Talk to a real person about your furnace control board replacement
No call center. The owner or one of his sons picks up.
(210) 600-5091