When you boondock regularly — no hookups, no campground services, no one nearby to help — you develop a different relationship with your rig’s systems than a weekend camper does. Everything has to work. You learn the failure modes, the warning signs, and the repairs before you need them, not during. The furnace on a Winnebago Forza is one of those systems you simply cannot afford to lose — when temps drop hard in the desert at elevation or you’re parked somewhere remote in November, a furnace that clicks but won’t light isn’t an inconvenience, it’s a safety problem. Nine times out of ten, that no-ignition failure traces back to either a worn igniter or a failing control board, and this guide walks you through diagnosing which one is the culprit and replacing it yourself, the same way it’s been done in the field — not in a shop.
The Igniter That Won’t Quit on a Cold-Start Furnace Failure
When your Suburban furnace clicks but won’t ignite—or ignites intermittently and dies after a few minutes—the hot surface igniter is almost always the culprit, especially on older Forza units running SF-35 and SF-42 cores. A weak or dead igniter won’t reach the temperature needed to light the burner, leaving you with a furnace that looks functional but delivers nothing but cold air.
What works
- Fires consistently on first demand, even after sitting through a cold night—no repeat ignition attempts or cycling.
- Drop-in fit for SF-20 through SF-35 series; arrives with the probe assembly and connector already attached, no splicing required.
- Reaches operating temperature in under 10 seconds, which means the control board recognizes a valid flame and holds the igniter energized for the full burn cycle.
What doesn’t
- OEM specs are finicky—if your control board is looking for a specific probe resistance, a mismatch will cause the board to fault and lock out, leaving you troubleshooting voltage and continuity instead of just swapping the part.
- Ships from overseas warehouse with typical Amazon delays; if you need heat in 24 hours, this won’t work.
I second-guessed myself halfway through the install when I saw the probe dimensions were slightly different from the OEM part sitting on the bench, but once seated and fired up, the control board recognized it immediately and held flame without hesitation. Fit For Suburban RV Furnace Parts 232286,Single Probe Gas Furnace Igniters Electrode with Wire Assembly, Camper Furnace For Suburban 232286 Above 934701426 SF-20, SF-25, SF-30, SF-35 (SF Series)
Fit For Suburban RV Furnace Parts 232286,Single Probe Gas
I replaced mine once and haven’t cycled the furnace since—holds flame on the first ignition attempt.
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