Why is my furnace ignitor not glowing?

Most likely because it's cracked or burnt out from old age—it's the most common part to fail on a modern furnace. It could also have a loose wire, or the furnace control board isn't sending power to it, but you should always check for a visible crack first.

How do I know if my furnace ignitor is bad?

The easiest way is to look at it. Kill the power, pull the furnace door off, and inspect it with a flashlight. If you see a thin crack or a white burn mark on the element, it's toast. The other big clue is the furnace blower will run, but the burners never ignite.

Can I replace a furnace ignitor myself?

Yeah, probably. If you're comfortable turning off the electricity and using a screwdriver or a nut driver, it's usually a pretty straightforward job. It's often just one or two screws and a plug. Just be gentle—the new one is fragile too! And don't touch the grey or black part with your bare hands.

How much does it cost to fix a furnace ignitor?

If you do it yourself, the part will cost you anywhere from $25 to $100. If you call a professional, expect to pay between $225 and $450, depending on the company, your location, and the specific furnace model.

Furnace Ignitor Not Glowing? Troubleshooting & Fixes from a 25-Year Pro

Quick Answer

Okay, here's the quick version. Your furnace ignitor isn't glowing and you've got no heat. Nine times outta ten, that little part has just burnt out. They're like lightbulbs, they don't last forever, especially the older silicon carbide (HSI) ones, or even newer nitride ignitors can fail. You can probably swap it yourself if you're handy; the part's maybe $30-150 depending on the model. Or you can call a guy like me, and you're looking at probably $250-$600 all said and done. It's the most common furnace ignition component failure I see every single winter.

Furnace Ignitor Not Glowing? Troubleshooting & Fixes from a 25-Year Pro visual diagram — Visual guide for diagnosing key fob issues

Common Symptoms

Furnace blower comes on but won't ignite the burners

No heat coming from the furnace, just cool air

Furnace clicks on and off without producing a flame

You can't see the ignitor glowing orange/red during startup

Possible Causes

Faulty or burnt-out ignitor: This is the most common cause, happens from simple old age and repeated heating/cooling cycles.

Loose electrical connections: The Molex plug connecting the ignitor can get loose from vibrations over the years.

Clogged condensate line: On high-efficiency units, a blocked drain trips a safety switch, which prevents the ignitor from getting power.

Bad furnace control board: The relay on the board that sends power to the ignitor has failed, which is a less common but more expensive repair.

Step-by-Step Diagnosis

Step 1

Shut off power to the furnace at the circuit breaker. This is a critical safety step.

Step 2

Remove the furnace access panel to expose the burner assembly.

Step 3

Locate the ignitor. It's a small element on a ceramic base, usually near the first burner.

Step 4

Visually inspect the ignitor with a flashlight for any visible cracks or white burn spots. If you see one, that's your problem.

Step 5

Check the wire plug connected to the ignitor. Make sure it's pushed in securely and isn't corroded or melted.

Step 6

(Advanced) If it looks okay, use a multimeter set to Ohms to test for continuity. An 'OL' reading means it's broken internally.

Furnace Ignitor Not Glowing? Troubleshooting & Fixes from a 25-Year Pro — Key fob troubleshooting and repair overview

DIY vs Professional Costs

Repair Type	DIY Cost	Professional Cost	Time Required
Cleaning a Dirty Ignitor	$0 - $10	N/A	30 minutes
Replacing a Faulty Ignitor	$30 - $150	$250 - $600	30-60 minutes
Control Board Replacement	$150 - $600 (Part Only)	$600 - $1200+	1-2 hours

Cleaning a Dirty Ignitor

DIY$0 - $10

ProN/A

Time30 minutes

Replacing a Faulty Ignitor

DIY$30 - $150

Pro$250 - $600

Time30-60 minutes

Control Board Replacement

DIY$150 - $600 (Part Only)

Pro$600 - $1200+

Time1-2 hours

When to Call a Professional Hvac

If you smell gas at any point. Stop, leave the house, and call your gas company and a professional immediately.
If you've replaced the ignitor yourself and the furnace still won't light. This means the problem is elsewhere, likely the control board or a safety switch.
If you are not 100% confident in your ability to work safely with 120-volt electricity.
If you suspect the issue is the main control board, as a mistake during replacement can be very costly.

Prevention Tips

Change your furnace filter religiously every 1-3 months. A dirty filter is the #1 cause of premature part failure.
Schedule an annual professional tune-up. A tech can spot a weak ignitor before it fails completely and leaves you cold.
Keep the area around your furnace clear of clutter and debris to ensure it has plenty of fresh air for combustion.
When replacing an old black ignitor, ask for a silicon nitride (grey) upgrade kit. They are far more durable and last much longer.

Furnace Ignitor Not Glowing? Troubleshooting & Fixes from a 25-Year Pro professional repair detail — Professional key fob repair and programming

Frequently Asked Questions

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