How to Replace an RV Furnace Blower Motor

By RVTroubleshoot Staff — If your furnace starts squealing, screeching, or humming louder than it used to, that’s your blower motor begging for attention. In most RV furnaces, the motor does double duty: it pushes combustion air outside and circulates cabin air inside. When it fails, you’ll lose both ignition and heat output — and on cold nights, that’s a bad combination.

Most RV furnaces are Suburban or Atwood/Dometic models. The process below applies to both — always confirm part numbers before ordering replacements.

When to Replace the Motor

Blower motors don’t usually die instantly; they get noisy, sluggish, or start tripping fuses first. If you notice:

Squealing or grinding when the furnace starts
Intermittent operation (starts, then stops after a few seconds)
Weak or no airflow from vents
A burnt smell near the furnace compartment

— it’s time to inspect the motor. Most OEM motors cost between $90–$150 and can be swapped with basic hand tools in under an hour.

Tools & Supplies

Phillips and flathead screwdrivers
1/4" nut driver or socket
Needle-nose pliers
Wire cutters/strippers and crimp connectors
New blower motor (exact replacement model)
Shop vacuum and rags
Multimeter (optional for diagnosis)

Safety First

Turn off propane at the tank.
Disconnect 12V power or remove the furnace fuse.
Allow the furnace to cool completely before working.

Step 1: Remove the Furnace Access Panel

Access varies by RV, but typically you’ll find the furnace under a cabinet or bench. Remove the exterior access door (four screws on most models). Inside, you’ll see two fans — one for exhaust and one for cabin air — both driven by the same motor shaft.

Step 2: Disconnect Wires and Fuel Line

Take a clear photo of your wiring before touching anything. Disconnect the two motor wires (usually black and red) and any quick-connect plugs. If your furnace has a gas line connected inside, disconnect it using two wrenches — one to back up the fitting and one to turn. Cap it temporarily for safety.

Mark each wire with tape before removing it — saves you from reverse-polarity mistakes later.

Step 3: Remove the Furnace (If Necessary)

In some rigs, you can reach the motor directly; in others, the furnace needs to slide out. Remove mounting screws and gently slide it forward. Support the weight — it’s heavier than it looks, especially with the combustion housing attached.

Step 4: Separate the Motor Assembly

With the furnace out or open, remove the screws holding the blower housing covers. Note how the fan blades sit on the motor shaft — usually one on each end. Loosen the set screws on each wheel and slide them off carefully. If they’re stuck, use penetrating oil and patience, not brute force.

Step 5: Install the New Motor

Position the new motor exactly as the old one was mounted. Align the flats on the shaft with the set screw holes in both fan wheels, and tighten securely. Don’t overtighten — you can crack the aluminum hub.

Reconnect the two motor leads. Most newer motors are polarity-sensitive, so red goes to +12V, black to ground. If reversed, the fans will spin backward and airflow will collapse.

Step 6: Clean and Reassemble

Vacuum out dust and debris from the furnace housing, especially near the burner and intake areas. A dirty blower can cause airflow restrictions and overheating. Replace any gaskets that tore during removal. Reinstall the furnace in its compartment and tighten all screws evenly.

Step 7: Test the System

Reconnect propane and 12V power.
Turn on the thermostat and listen for ignition.
The blower should start smoothly, then ignite after 15–30 seconds.
Check outside for clean exhaust flow — no sputtering or smoke.

If the motor hums but doesn’t spin, double-check the polarity and ensure both fans are free to rotate. A binding blower wheel can stall a brand-new motor.

Bonus: Extend the Life of Your New Motor

Vacuum vents and return air intakes every few months to reduce dust buildup.
Run the furnace for 5–10 minutes monthly during off-season to keep bearings lubricated.
Use dielectric grease on electrical connectors to prevent corrosion.
Keep wasps or mud daubers from nesting in the exhaust tube — they can block airflow and burn up motors fast.

Common Mistakes to Avoid

Using the wrong rotation motor — clockwise vs. counterclockwise matters.
Forgetting to re-seal the exhaust flange — small leaks cause soot and odor inside the RV.
Crimping wires without heat-shrink — they’ll corrode and fail months later.
Reinstalling fan blades backwards — mark orientation before removal.

Final Thoughts

Replacing a furnace motor might look intimidating, but it’s really just a mix of wiring and careful mechanical work. Take photos, stay organized, and give yourself time. Once you’ve done it once, it becomes another “no big deal” maintenance task — and you’ll never have to freeze in your own camper again.

If your furnace still acts up after a new motor, check for weak ground, low voltage under load, or a faulty time-delay relay. But in most cases, a clean install and good airflow bring the heat roaring back the first try.