Let me tell you about last Tuesday night.

We’re parked at our favorite spot near Canyon Lake, temps dropped to 28 degrees, and around 3 AM—you guessed it—the furnace kicked off. Michael and I both woke up to that specific kind of cold that makes you wonder if you’re camping or cryogenically frozen.

Here’s the thing nobody tells you when you buy an RV: your furnace has a personality. And sometimes, that personality is “dramatic diva who quits when you need them most.”

Why RV Furnaces Are Weirdly Temperamental

After years of living in our RV full-time and fixing hundreds of furnaces for other folks, we’ve learned that RV furnaces fail for the dumbest reasons. Not complicated mechanical failures—just weird little things that add up.

The sail switch gets dirty. This little guy is basically a flap that proves air is moving through your furnace. Dust builds up, the flap gets stuck, and your furnace says “nope, not today.”

The battery voltage drops just enough. Your furnace is picky about power. If your battery dips below about 10.5 volts, the control board throws a fit and shuts everything down. Even if your lights still work fine.

Spiders. I wish I was kidding. Spiders love to build homes in the exhaust vent during summer. Come winter, your furnace can’t breathe, and it quits.

What We Did at 3 AM (So You Know What to Do Too)

First, Michael checked the obvious stuff while I made coffee—because nothing happens before coffee, even emergencies.

We pulled the furnace cover and looked at the sail switch. Yep, dusty. A quick cleaning with a soft brush, and we were back in business. Total time? Maybe 15 minutes.

But here’s what we SHOULD have done two weeks earlier: preventive maintenance. Clean the sail switch, check the battery, make sure the vents are clear. All the boring stuff that keeps you from waking up freezing.

The Real Lesson Here

RV life isn’t always Instagram-worthy sunsets and campfire s’mores. Sometimes it’s you and your spouse huddled under blankets at 3 AM, troubleshooting a furnace with a headlamp and a screwdriver.

And honestly? That’s part of what makes this lifestyle so good. You learn stuff. You figure things out. You become the kind of person who can fix a furnace in the middle of the night and still laugh about it over morning coffee.

Your Furnace Survival Checklist

Before the next cold snap hits, do yourself a favor:

Pull the furnace cover and clean the sail switch

Check your battery voltage (12.5+ volts is healthy)

Inspect the exterior exhaust vent for blockages

Test-run your furnace before you actually need it

Keep a spare furnace sail switch on hand

Or, if you’re in the New Braunfels area and don’t feel like crawling around in your RV, give us a call. We’ll come to you, check everything, and make sure you stay warm all winter.

Because nobody should have to wake up frozen at 3 AM. Once is enough for all of us.

Stay warm out there,

Alisha & Michael

RV Rescue Rangers

P.S. - If your furnace is acting weird right now, don’t wait until 3 AM to deal with it. Seriously. Learn from our mistakes.