After buying, repairing, and reselling more than thirty rigs, I’ve crawled into every corner of every coach body style you can name. I know exactly which systems manufacturers cut corners on, which repairs look scary but are actually straightforward, and which ones will drain your wallet if you wait too long. The furnace on a Jayco Redhawk falls squarely into that last category — when the igniter fails or the control board starts acting up, most owners assume the whole unit is shot and either freeze through a trip or hand a shop a blank check, but the reality is that a bad igniter or a failing control board is one of the most replaceable components in your entire heating system. I’ve seen rigs sitting on dealer lots for pennies because the previous owner couldn’t get the furnace to light, not realizing the fix was under two hours and less than a hundred bucks in parts. This guide walks you through exactly what I do when I pick up a Redhawk with a dead furnace — no guesswork, no unnecessary part swaps, just a clean diagnosis and a repair done right.
Parts & Tools You’ll Need
- Suburban RP-35Q 35,000 BTU/h RV Replacement Core for Suburban Furnace Series SF-35, SF-35Q, SF-42, SF-42Q, and SF-Q (2609A) — Suburban/Atwood RV furnace (replacement unit)
- 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) — Furnace igniter electrode
- DTAIR 33082 Sail Switch Replacement for Select Dometic Atwood RV Furnace(Pack of 2) — Furnace sail switch
- 520814 Rv Water Heater Module Board Ignition Control Circuit Board Compatible with Suburban Furnace SW4D, SW6D, SW6DE, SW12D, SW6DEM RV Water Heaters,Replace 520814 520820 520871 33550L (With lid) — Furnace circuit board / control board
- DTAIR 33082 Sail Switch Replacement for Select Dometic Atwood RV Furnace(Pack of 2) — Furnace high-limit switch
- Suburban 232684 RV Furnace 12v SF-Series DC Blower Motor, SF-35, SF-35F, SVF-35, SF-42, SF-42F OEM Caliber — Furnace blower motor (12V DC)
- RV Carbon Monoxide & Propane Gas Alarm, Briidea Dual LP/CO Detector with Separate LED Indicator Light, 100dB Loud Alarm, 12 VDC, Black — Propane/CO combo detector alarm
- FKM Pro Digital Multimeter Tester TRMS 6000 Counts,Smart Rechargeable Voltmeter 5″Color LCD,Auto-Ranging Automotive Multimeters,for AC/DC Current/Voltage,NCV,Ohm,Capacitance,Resistance,Continuity,Temp — Digital multimeter
Step 1: Diagnose Furnace Igniter and Control Issues
Start by turning off the propane supply at the tank and switching off the 12V power to your furnace at the main RV electrical panel. Use your digital multimeter set to DC voltage mode to test the igniter electrode for continuity—you should read between 0.1 to 2 ohms of resistance when the igniter is at room temperature. If the multimeter shows an open circuit (infinite resistance) or the furnace fails to ignite after multiple attempts, the igniter electrode and/or control board require replacement.
Step 2: Remove Furnace Access Panels and Components
Locate your Jayco Redhawk’s furnace access door, typically found in the external lower cabinet or interior closet space. Remove the two to four Phillips head screws securing the furnace cover panel and carefully set aside the metal enclosure to expose the burner assembly, igniter electrode, and circuit board mounted on the interior frame. Take a photograph of the wiring connections before disconnecting anything to ensure accurate reassembly.
Step 3: Disconnect Electrical Harnesses from Control Board
Identify all connectors linked to the furnace circuit board—you’ll typically find four to six multi-pin harnesses connecting the control board to the blower motor, sail switch, high-limit switch, and igniter electrode. Carefully pull each connector straight out using firm, even pressure; avoid twisting or bending the plastic connectors. Label each disconnected harness with painter’s tape and a marker to prevent cross-wiring during reinstallation.
Step 4: Remove Old Igniter Electrode and Mounting Hardware
Locate the furnace igniter electrode, a small ceramic or metal probe positioned near the burner flame sensing area. Unscrew the single mounting bolt (typically 1/4-inch) securing the electrode to the burner box frame and slide the electrode connector off its terminal block. Inspect the removed electrode for visible cracks, discoloration, or deposits; these confirm ignition failure and justify replacement.
Step 5: Install New Control Board and Igniter Assembly
Position the new furnace circuit board in the exact location of the original unit, ensuring mounting holes align with the frame studs. Insert the new furnace igniter electrode into its mounting bracket and secure with the 1/4-inch bolt, tightening firmly but not over-torquing (approximately 8-10 foot-pounds). Connect the igniter electrode terminal to the control board’s designated two-pin connector, ensuring the connection clicks firmly into place.
Step 6: Reconnect All Electrical Harnesses and Verify Polarity
Using your labeled tape reference, reconnect each harness to its corresponding control board terminal in reverse order of disconnection. Pay special attention to the sail switch and high-limit switch connectors—most modern boards are polarity-sensitive, and reversed connections will prevent ignition. Double-check that the blower motor connector (typically a three-pin terminal) is seated completely, then visually inspect all connections for loose or partially inserted pins.
Step 7: Test Furnace Ignition and Safety Systems
Restore 12V power at the main RV electrical panel and turn the propane supply back on at the tank. Set your Jayco thermostat to heating mode at approximately 75°F and listen for the blower motor to activate within 30 seconds followed by the characteristic igniter spark (a clicking sound). Confirm the furnace achieves stable flame within 5 seconds of ignition; if the flame extinguishes or the burner fails to light after three attempts, shut down immediately and recheck all electrical connections. Finally, test your propane/CO combo detector alarm to verify it registers normal CO levels (under 35 ppm) during furnace operation.