RV Furnace Clicks But Won't Ignite: Causes, Fixes, and When to Replace Parts

If you've ever climbed into a cold rig, flipped on the furnace, and heard that familiar click-click-click with no whoosh of heat afterward, you know how frustrating it is. The good news: this is one of the most common RV furnace complaints, and in most cases it's fixable without a service call — as long as you know where to look.

This guide walks through why your RV furnace clicks but won't light, how to diagnose the exact cause, and which parts typically solve the problem.

Check out our parts guide here

Why the Clicking Happens in the First Place

That clicking sound is the igniter (or spark electrode) trying to create a spark to light the burner. On most modern RV furnaces — Suburban and Atwood/Dometic being the two big brands — the furnace goes through an automatic sequence:

1. The thermostat calls for heat
2. The circuit board energizes the blower motor
3. Once airflow is confirmed (via a sail switch or pressure switch), the gas valve opens
4. The igniter sparks to light the burner
5. A flame sensor confirms ignition; if it doesn't detect flame within a few seconds, the board cuts gas and tries again (usually 3 attempts) before locking out

If you hear clicking but no ignition, something is breaking that chain — either there's no gas reaching the burner, the spark isn't strong enough, or the flame sensor isn't confirming a flame even though one exists.

Most Common Causes (In Order of Likelihood)

1. Low or Empty Propane Tank

It sounds obvious, but it's the #1 cause. Check your propane level first. Even a tank that's not fully empty can have too little pressure to sustain a flame, especially in cold weather.

2. Dirty or Corroded Igniter/Electrode

The electrode that creates the spark can accumulate carbon, dirt, or corrosion over time, weakening the spark so it can't ignite the gas-air mixture. This is especially common if the furnace hasn't run in a while (like after winter storage).

Fix: Remove the furnace access panel and inspect the electrode. A light cleaning with fine sandpaper or an electrode file can restore the spark. If it's cracked or pitted, replace it.

3. Gas Valve or Orifice Issues

If the electrode sparks fine but there's no gas flow, the problem may be a faulty gas valve or a clogged orifice (often from dust, insects, or debris — a real issue for furnaces that sat unused over summer).

4. Sail Switch or Pressure Switch Problems

This safety switch confirms the blower is pushing enough air before the gas valve is allowed to open. If it's stuck, misaligned, or wired incorrectly, the furnace may click (spark) without ever opening the gas valve, since the board never gets the "airflow confirmed" signal.

5. Weak or Failing Circuit Board

Circuit boards regulate the whole ignition sequence. A failing board can cause erratic clicking, intermittent ignition, or a furnace that seems to almost light but shuts down repeatedly.

6. Loose or Corroded Wiring Connections

Vibration from road travel loosens connectors over time. Check the wiring harness at the circuit board, gas valve, and igniter for corrosion or loose pins.

7. Dirty Flame Sensor

Some models use a separate flame sensor (sometimes combined with the electrode) that confirms a flame is actually present. If it's dirty or misaligned, the board may cut gas immediately after ignition, making it seem like the furnace never lit at all — even though it briefly did.

Step-by-Step Troubleshooting

1. Check propane level and that other appliances (stove, water heater) work on gas. If nothing runs on propane, it's a supply issue, not the furnace.
2. Listen carefully to the sequence. Does the blower run before the clicking starts? If not, suspect the sail switch or board.
3. Watch (or listen) for a whoosh of ignition that cuts out quickly. This points to a flame sensor problem rather than an ignition problem.
4. Inspect the electrode and burner area for carbon buildup, corrosion, or dirt/debris/insect nests in the burner tube.
5. Check all wiring connections at the board, valve, and igniter for looseness or corrosion.
6. If comfortable with basic electrical testing, a multimeter can confirm voltage is reaching the gas valve and igniter as expected — otherwise this step is best left to an RV tech.

Parts That Commonly Fix This Issue

Once you've identified the culprit, most of these are DIY-replaceable with basic hand tools:

• Igniter/electrode assemblies — the most frequently replaced part for this exact symptom
• Sail switches / pressure switches
• Circuit boards (furnace-specific, matched to your Suburban or Atwood/Dometic model)
• Gas valves
• Flame sensors
• Wiring harnesses and connector kits

Matching the part to your exact furnace model number matters — Suburban and Atwood/Dometic parts are not interchangeable, and even within a brand, board and igniter designs vary by model year.

When to Call a Professional

If you've checked propane supply, cleaned the electrode, and confirmed wiring is intact but the furnace still won't ignite, it may be a circuit board or gas valve failure that requires more diagnostic equipment — or the issue could involve venting or safety components that are worth having a certified RV tech verify, since furnace safety systems exist for good reason.

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Looking for the exact igniter, sail switch, or circuit board for your RV furnace? Browse our full catalog of Suburban and Atwood/Dometic replacement parts at RVFurnaceParts.com to get your heat running again before your next trip.