Rockwood/Flagstaff – Furnace Igniter & Control Board Replacement

As someone who’s logged over 80,000 miles across North America in three different rigs, I, Drew Callahan, have learned a thing or two about RV maintenance. Most RV owners don’t think about their furnace igniter or control board until it’s too late—like when it dies in subfreezing temperatures. At that point, a $120 part can quickly turn into a $400 emergency call from a mobile technician who might not show up for two days. Trust me, I’ve been there. On Rockwood and Flagstaff units, these components tend to fail predictably, but the good news is that they’re fixable if you catch the problem early. When your furnace starts rapid-clicking without igniting, blows out cold air instead of warmth, or goes completely silent, you’re likely facing a problem with either the igniter or the control board. In frigid conditions, this situation escalates from an annoying breakdown to a genuine health and safety crisis. I’ve tackled this repair on my own rigs enough times that I can guide you through the process step by step, without any dealer jargon. Just the real work I’ve had to do when staying warm was non-negotiable.

When the Control Board Quits, Everything Stops

When your Rockwood or Flagstaff furnace’s control board goes dead, you’ll get zero response from the system—no spark, no clicking relay, no ignition sequence at all. This circuit board orchestrates the entire heating cycle, and without it functioning, nothing else in the system matters.

What Makes This Replacement Work

• It slots directly into most Suburban and Atwood furnaces as a straightforward swap—simply unplug the old connector and plug in the new board, with no harness modifications or intermediate adapters required.
• You’ll quickly know if the board was really your issue—heat returns immediately with a faulty board replacement, so you’ll find out within moments if something else is broken.
• This replacement cuts through the guesswork of chasing down igniter pins and sail switch continuity when the real problem was sitting on the furnace housing all along.

Where This Replacement Falls Short

• You’ll need to identify your furnace model precisely beforehand—installing the wrong board is a common mistake, and it won’t work even remotely “well enough.”
• This won’t solve anything if your actual issue is a burned-out igniter or a blocked propane line—the board is only the answer when the board itself is the broken part.

I recall standing in my RV at midnight, furnace completely unresponsive, and I was anxious about whether I’d just wasted $40 on a part that wouldn’t do anything. But the moment I plugged that new board in and heard the spark electrode fire up, I knew I’d made the right call. If your furnace is dead and your multimeter shows no voltage at the board connector, go ahead and grab a furnace circuit board / control board and stop second-guessing yourself.

Parts and Tools

• Replacement furnace circuit board / control board matched to your Rockwood or Flagstaff furnace model number — check current price
• Hot surface igniter element (glow plug style) if your furnace uses one instead of a spark igniter
• Needle-nose pliers or tweezers for disconnecting small wire terminals without damage
• Multimeter set to measure DC voltage and continuity
• Small flashlight or headlamp to see inside the furnace compartment
• Masking tape and marker for labeling wire connections before removal

Step-by-Step Instructions

Step 1: Kill power to the furnace at the breaker

Locate your RV’s main electrical panel and switch off the 12V DC breaker that feeds the furnace. If your furnace also has a 120V AC connection, flip that breaker too. Wait 30 seconds to ensure all capacitors on the control board have discharged. This prevents accidental shock and protects the new board from voltage spikes during installation.

Step 2: Access the furnace compartment and photograph the wiring

Open the access panel on your furnace—usually held by two or three screws on the front or side. Before touching anything, take a clear photo of the entire control board and all wire connections. This photo is your insurance against confusion during reassembly. Note which wires connect to the igniter, thermostat, and gas valve. If the wires use color-coded terminals, photograph those too.

Step 3: Test the igniter for continuity and resistance

Set your multimeter to the ohms setting. Disconnect the igniter wires at the control board terminals. Touch the multimeter probes to the igniter leads. A working hot surface igniter reads between 40 and 100 ohms; a spark igniter should show continuity with no open circuit. If the reading is infinite (open circuit) or zero (short), the igniter is dead and must be replaced. If it tests good, the control board is your culprit.

Step 4: Disconnect the old control board carefully

Using needle-nose pliers, gently pull each wire terminal straight out of its socket on the control board. Do not yank or twist—these connectors are fragile. As you disconnect each wire, immediately apply a small piece of masking tape to the wire and write its terminal location (e.g., ‘TH1’, ‘IGN’, ‘GV’) with your marker. This labeling prevents cross-wiring the new board, which will cause the furnace to malfunction or fail to ignite.

Step 5: Remove the old board and install the new one

Unscrew the control board from its mounting bracket—usually two or three screws. Slide the new board into place and secure it with the same screws, tightened snugly but not over-torqued. Reconnect each wire to its matching terminal on the new board, using your photo and tape labels as your guide. Double-check every connection before moving forward; a loose or reversed wire will prevent ignition.

Step 6: Test igniter continuity on the new board

With the board installed and all wires connected, set your multimeter to ohms again. Probe the igniter terminals on the new board. You should see the same resistance reading as before (40–100 ohms for hot surface, continuity for spark). If the reading is open or shorted, stop and recheck your wire connections. A bad reading means the new board is defective or a wire is loose.

Step 7: Restore power and run a full ignition cycle

Close the furnace access panel and flip the 12V DC breaker back on. If you have a 120V AC breaker, restore that too. Set your thermostat to heat mode and raise the temperature above the current cabin temperature. Listen for the relay click, then the igniter spark or glow. The furnace should ignite within 10 seconds and blow warm air. If it clicks rapidly without igniting or blows cold air, turn it off and recheck all wire connections.

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