Crossroads Redwood – Furnace Igniter & Control Board Replacement

I’ve got my Crossroads Redwood sitting in a pull-through right now, and I’m looking at the furnace access panel I pulled off the sidewall about an hour ago. Inside that compartment lives two components that almost nobody thinks about until they fail: an igniter and a control board. Those two parts work in tandem, and when one goes bad—especially on a night when the temperature is dropping toward freezing—you realize pretty fast how much you depend on them. I’ve now replaced both, separately and together, and I’ve learned when to swap just the broken piece and when it makes more sense to tear out the whole furnace and drop in a fresh unit. This guide walks through exactly what I’ve discovered during those repairs, including the tools you actually need, the cost difference between the two approaches, and the trick that keeps you from sitting in a cold rig while you wait for a service appointment that might not come for another week.

Understanding Your Furnace’s Two Critical Components

Before you touch anything, it helps to understand what these two parts actually do. Your igniter is a ceramic electrode that reaches roughly 1,500 degrees when your furnace kicks into its firing sequence—that heat is what sparks the propane and gets the burner lit. Your control board is the brain that orchestrates the whole thing: it reads the signal from your thermostat, energizes the igniter when it’s time, and opens the gas valve in the proper order. Lose either one, and your furnace becomes nothing more than a cold metal box attached to your sidewall.

The igniter burns out first, most of the time, because it’s under constant thermal stress. The ceramic cracks from repeated heating-and-cooling cycles, and eventually it stops conducting electricity. Your control board can give up for different reasons—moisture seeping in during humid months, simple age, or damage from an electrical spike if your rig’s charging system has acted up. Every so often both pieces fail together, and that’s when you hit the crossroads between fixing one part or rebuilding the whole system.

The Individual Component Replacement Route

If the problem shows up early and all the signs point to just the igniter—you’re hearing endless clicking and catching a whiff of propane, which means the valve is opening but the spark isn’t catching—then swapping only the electrode is your thriftiest option. You’ll want to bring a multimeter to the job so you can verify there’s voltage arriving at the igniter during the firing cycle, and you’ll need to get to the furnace burner box itself, which usually requires removing a panel from somewhere on your RV’s exterior or interior wall.

The electrode runs between $20 and $40, and the swap itself takes roughly 30 minutes. You unplug it from the wire leads, slide it out of its socket, and push the new one in—no specialized equipment needed. The gamble is that you spend an hour on this work and then discover the control board is also dead, leaving you with no heat and an incomplete fix.

The Full Replacement That Saved Me From a Freezing Night (and a Repair Bill)

When your troubleshooting points to a dead control board, or when you’re staring at multiple failed parts, sometimes ripping out the whole furnace and installing a fresh one moves faster and costs less than chasing components one at a time. In a Crossroads Redwood, the Suburban/Atwood replacement sits right down into the old unit’s footprint without requiring new propane plumbing or rewiring the blower motor.

Parts and Tools

• Replacement igniter assembly matched to your furnace model (ceramic electrode with mounting bracket and wire connector)
• Replacement control board matched to your furnace model and voltage rating
• Wire strippers and crimpers for reconnecting igniter and board harnesses
• Multimeter set to measure DC voltage and resistance
• Screwdrivers (Phillips and flathead) for panel and component fasteners
• Propane wrench or adjustable wrench for gas line fittings if disconnecting supply
• Camera or phone for photographing wire routing and connector positions before removal

Step-by-Step Instructions

Step 1: Isolate propane and 12V power to the furnace

Turn off the propane supply at your rig’s main tank valve. Locate your furnace’s 12V power source—usually a dedicated breaker in the main panel or a fused line running from your battery—and switch it off or pull the fuse. Wait five minutes to ensure any residual charge dissipates. This prevents accidental ignition or electrical shock while you work inside the compartment. Do not proceed until both supplies are confirmed off.

Step 2: Remove the furnace access panel and photograph the layout

Unbolt or unscrew the exterior access panel on your Redwood’s sidewall. Before touching anything inside, take clear photos of the igniter position, control board location, and all wire connections from multiple angles. Note which wires connect where—colors fade and memory fails. This photograph becomes your wiring diagram if connectors are unmarked or if you need to troubleshoot later.

Step 3: Test the igniter for continuity and resistance

Set your multimeter to the resistance (ohms) setting. Disconnect the igniter’s wire connector at the control board. Touch the multimeter probes to the igniter’s two terminals. A working igniter typically reads between 40 and 100 ohms; an open circuit (infinite resistance) or a short (near zero) means it has failed. If the reading is normal, the problem likely lies with the control board instead. Document this result before proceeding.

Step 4: Disconnect and remove the failed igniter

Unplug the igniter connector from the control board. Locate the igniter’s mounting bracket—usually a single bolt or two screws holding it to the furnace burner assembly. Remove the fasteners and carefully withdraw the igniter, noting its orientation and any ceramic insulation sleeves. Do not force it; if it sticks, apply penetrating oil and wait ten minutes. Keep the old igniter as a reference for the replacement’s correct seating angle.

Step 5: Install the replacement igniter and verify fit

Slide the new igniter into the mounting bracket, matching the angle and depth of the original. The ceramic tip should sit at the same distance from the burner opening as the old one did. Tighten the mounting fasteners snugly but do not over-torque ceramic components—hand-tight plus a quarter turn is usually sufficient. Reconnect the wire harness to the control board, ensuring the connector seats fully and clicks if it has a locking tab.

Step 6: Test the control board for voltage and ground

Restore 12V power to the furnace by switching the breaker back on or reinserting the fuse. Set your multimeter to DC voltage. Probe the control board’s power input terminals—you should read approximately 12V. Check for a solid ground connection by testing between the negative terminal and a known ground point on the furnace chassis. If voltage is absent or ground is floating, the control board is likely the culprit and must be replaced before testing the igniter.

Step 7: Replace the control board if needed

If voltage testing revealed a dead board, turn off 12V power again. Photograph all wire connections to the board before disconnecting anything. Unbolt the board from its mounting location and unplug every connector. Install the replacement board in the same orientation, reconnect all harnesses in the order shown in your photographs, and secure it with the original fasteners. Double-check that no wires are pinched or routed near sharp edges.

Step 8: Restore power and test the furnace ignition cycle

Turn 12V power back on and restore propane at the main tank valve. Set your thermostat to heat mode and raise the setpoint above the current temperature. Listen and watch through the access panel for the igniter to glow orange-red within 10 seconds, followed by the sound of the gas valve opening and the burner lighting. If the igniter glows but gas does not flow, or if nothing happens at all, turn everything off and review your wire connections against your photographs. A successful light-off confirms both the igniter and control board are functioning.

What works

• Direct connector compatibility—your propane and 12-volt leads plug straight in without cutting or splicing anything
• No more guessing about which part is actually dead; you go from cold furnace to working heat in less than two hours
• You get a brand-new igniter and control board instead of installing a replacement component that might already have a few years of wear on it

What doesn’t

• Excessive spending if your actual problem is nothing more than a $30 igniter—you’ll shell out four times that amount just to replace the entire unit
• Delivery windows stretch to 2–3 weeks in the winter months, which means you need to catch the malfunction before the cold snap arrives

My Personal Decision Point

I stood in my RV at 11 p.m. on a 28-degree night, multimeter in hand, staring at a control board that wouldn’t register any voltage—and realized I didn’t have the time or certainty to diagnose six different components. That’s when I decided to order a Suburban/Atwood RV furnace replacement unit and skip straight to the fix.

My replacement unit showed up in five business days, which gave me enough lead time to block off a work window before the temperature really nose-dived. The second I unpacked it and matched the connectors to my existing setup, I was confident in the call. Taking out the old furnace meant unplugging three separate connectors and unbolting two mounting brackets—roughly 15 minutes of work. The new unit went straight in, every connection seated firmly, and when I fired up my thermostat, that igniter caught immediately.

Installation Tips From the Parking Lot

If you decide to do a full unit swap, photograph everything on your old furnace before you yank any connectors. Lay the new furnace down on a clean towel and visually match it against the old one—make sure there aren’t any surprises in the design. Keep a multimeter and a decent flashlight nearby; you’ll want both to check that connectors are making solid contact. After you’ve bolted everything in place, resist the urge to crank your thermostat right away. Give it a full 24 hours if the weather allows—that pause lets any internal moisture evaporate out. I know it feels overly cautious, but it doesn’t cost you anything and it buys peace of mind for a component you’re going to be counting on through the winter.

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