Every fall, my phone starts ringing the same week: the first cold night hits, someone turns on their RV furnace, and nothing happens. The fan runs but the air stays cold, it clicks and shuts off, or it just sits there.

If that's you, I'm sorry you're cold. The good news is that most RV furnace problems come down to the same few things, and some of them you can check yourself in a few minutes before you ever call me.

The short answer: most of the time it's 12-volt power, propane, or airflow. Check those first. If the furnace still won't light, or it keeps shutting off, that's when it needs proper testing.

I've sorted the problems below by what you're seeing, so you can skip to yours.

🔧 First, What's Normal

A lot of calls I get are for a furnace that's actually working fine. Here's what a normal start looks like:

The fan comes on first and runs for about 15 to 30 seconds before the burner lights.
The air blows cool for a minute or two until the furnace warms up.
When the RV reaches the set temperature, the burner shuts off but the fan keeps running a minute or two to cool the furnace down.
If the burner doesn't light, most RV furnaces try about three times and then lock out until you reset them.

Here's the part most people don't know: your furnace burns propane, but it runs on 12-volt power. The fan has to push enough air to close a small switch (the sail switch) before the furnace is allowed to light. If any step in that chain fails, the whole thing stops.

⚠️ Problem 1: Nothing Happens at All

No fan, no click, no sound when you turn up the thermostat.

Check the thermostat. Make sure it's set to heat or furnace, not cool or fan, and set above the room temperature. If it takes batteries, try fresh ones.
Check your 12-volt power. Plug the RV into shore power or charge the battery, then try again.
Check the fuse. Look for the furnace fuse in the RV's 12-volt fuse panel.

One thing I'll tell every customer: if that fuse blows again right away, don't keep replacing it. Something is causing it, like a shorted wire or a blower motor on its way out. That needs to be found. See my RV Electrical Repair page.

⚠️ Problem 2: The Fan Runs but It Won't Light

This is the call I get the most. The fan runs, but the burner never lights and the air stays cold.

Check your propane. Make sure the tank has gas and the valve is open. Here's a quick test: if your stove burners won't light either, the problem is most likely your propane supply (the tank, valve, or regulator), not the furnace. After storage or a tank swap, light a stove burner first to push the air out of the lines.
Check your battery. A weak battery can make the fan spin too slowly to close the sail switch, so the furnace never even tries to light. This is one of the most common causes I find.
Dirty airflow. Dust, pet hair, and debris in the blower or around the sail switch can keep it from closing.

If your power, propane, and airflow are all good, it's usually the sail switch, igniter, gas valve, or control board. That's where I come in with proper testing, so you're not paying for parts you didn't need.

⚠️ Problem 3: It Lights, Then Shuts Off

The burner lights, runs a little while, then shuts off, sometimes over and over.

Blocked airflow. Closed floor vents, something in front of the return air grille, or a crushed duct lets the furnace overheat, and a safety switch shuts it down.
Blocked outside vent. The furnace vent on the outside of your RV is a favorite spot for wasps and mud daubers, especially after the RV sat all summer. Take a look.
Low voltage. The voltage can drop when everything runs at once, which can shut the furnace down.

If the vents are open and the outside vent is clear, it's likely a limit switch or flame sensing problem, and that needs testing.

⚠️ Problem 4: It Clicks but There's No Heat

You hear clicking or ticking, it tries to light, then goes quiet.

Low propane or air in the lines is the first thing to rule out.
A worn igniter or a dirty burner can keep it from lighting.
After about three tries, it locks out. See "How to Reset Your Furnace" below.

⚠️ Problem 5: It Runs, but the RV Never Warms Up

Make sure every floor vent is open and nothing is blocking the return air grille.
Weak airflow often comes from a dirty blower, a tired blower motor, or low battery voltage.
On a really cold night, even a healthy furnace can struggle in a big RV. That doesn't always mean something is broken.

🔄 How to Reset Your Furnace

Most RV furnaces don't have a reset button. To clear a lockout:

Turn the thermostat off and wait at least a minute.
Turn it back on, set to heat, above the room temperature.

If it locks out again, stop there. Resetting it over and over won't fix it. Something is causing it, and it needs to be checked.

🚨 Please Be Safe

If you smell propane, turn the propane off at the tank, don't flip any switches, get everyone out of the RV, and call for help. If your carbon monoxide or propane alarm goes off, get out and don't use the furnace until it's been checked. Test those alarms before heating season starts.

Please don't open up the furnace, take apart the gas valve, or work on the wiring yourself. Leave that part to me.

While you're waiting on a repair, I'd hate for you to be cold. If you use a small electric space heater, don't plug it into the RV's outlets. At home, plug it into its own dedicated outlet from the house. If you live at a campground, use the dedicated 20-amp outlet on the campground pedestal. Either way, use a heavy-duty extension cord sized for the heater, not a light household cord.

🛠 Why I Recommend a Yearly Furnace Service

A furnace that sat unused for months collects dust, debris, and insect nests. A clean and service before the first cold night prevents most of the problems above. I clean the burner area and blower, check the outside vent, check the electrical connections, test the ignition, and make sure it has proper airflow and runs the way it should.

My prices are flat rate, so you know the cost before I start. See my Pricing & Service Fees page.

❓ Questions I Get Asked a Lot

Why does my RV furnace blow cold air at first?

That's normal. The fan runs about 15 to 30 seconds before the burner lights, and the air takes a minute or two to warm up. If it blows cold the whole time, see Problem 2.

Why does my RV furnace keep shutting off?

Most of the time it's overheating from blocked airflow or a blocked outside vent, or it's low battery voltage. See Problem 3.

Can I run my RV furnace without a battery?

No. Even though it burns propane, the fan, control board, and igniter all need 12-volt power. When you're plugged into shore power, your RV's converter usually supplies it.

📍 Need Your Furnace Looked At?

Comic: an RV owner in the snow, confused by his open furnace with tools everywhere, and if all else fails, a Wayfare Mobile RV Repair technician fixes the furnace while the owner relaxes warm inside with a hot drink.

I come to your RV, whether it's in your driveway, at a campground, or in a storage lot, so you don't have to tow it to a repair shop and wait weeks in the middle of heating season. I work on Suburban and Atwood/Dometic furnaces throughout Harford County, including Bel Air, Forest Hill, Aberdeen, and the surrounding areas.

One tip that saves time: when you reach out, send me a photo of your furnace's data plate (the model and serial sticker). That way I can bring the right parts and try to finish in one trip.

📞 Call or text me at 443-987-5050, and I'll tell you straight what's wrong, what it will cost, and what your options are before any work begins.

👉 Learn more: RV Furnace Repair

RV Furnace Not Working? Common Problems, Simple Checks, and When to Call