Forest River Sunseeker – Furnace Igniter & Control Board Replacement

Forest River Sunseeker – Furnace Igniter & Control Board Replacement

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Complete repair guide for the Forest River Sunseeker – Furnace Igniter & Control Board Replacement. Follow these steps to diagnose and fix the issue yourself.

Parts & Tools You’ll Need

Step 1: Diagnose Furnace Failure and Prepare Work Area

Start by verifying the furnace isn’t producing heat and listen for the blower motor activation when you turn on the thermostat. Locate your RV’s propane shutoff valve and turn it to the OFF position, then disconnect the negative battery terminal to de-energize the 12V system. Open all windows and vents to ensure proper ventilation, and gather your digital multimeter, screwdrivers, and the replacement parts on a clean work surface near the furnace access panel.

Step 2: Remove Furnace Access Panel and Disconnect Components

Unscrew and carefully remove the furnace access panel located beneath or beside your Sunseeker’s heating unit, noting the orientation of any gaskets for reinstallation. Disconnect the sail switch connector (typically a two-pin harness), the igniter electrode wire, and the circuit board power connectors by gently prying the clips upward. Photograph or label each connection with painter’s tape to ensure accurate reassembly during reinstallation.

Step 3: Test and Replace the Furnace Igniter Electrode

Using your digital multimeter set to resistance (ohms), test the igniter electrode by probing its terminals—you should read between 40-80 ohms for a functional electrode; any reading outside this range indicates failure. Remove the old igniter by unbolting it from the furnace burner box (typically two ¼-inch bolts), and install the new furnace igniter electrode in the identical position, torquing bolts to 15-18 inch-pounds. Ensure the electrode tip sits approximately 1/8-inch from the burner cup opening for proper spark gap.

Step 4: Inspect and Replace the Furnace Control Board

Examine the old circuit board for visible burn marks, corrosion, or cracked solder joints around the relay components, which indicate thermal or electrical failure. Carefully disconnect any remaining wired connections (thermistor, high-limit switch leads) and remove the two mounting brackets securing the board to the furnace chassis. Mount the new furnace circuit board in the identical position using the original brackets, ensuring all components face outward for accessibility.

Step 5: Reconnect All Electrical Harnesses and Verify Connections

Reattach the sail switch connector by aligning the keyed pins and pressing firmly until the clip locks with an audible click. Reconnect all circuit board power leads, thermistor wires, and high-limit switch connections in the same positions documented during removal, double-checking that no wires are pinched between the access panel and furnace body. Use your multimeter to verify continuity on all reconnected circuits before proceeding to the next step.

Step 6: Reinstall Access Panel and Restore Power Systems

Reposition the furnace access panel gasket in its original groove, then secure the panel with all screws torqued evenly at approximately 25-30 inch-pounds to create a proper seal. Reconnect the negative battery terminal, then turn the propane shutoff valve to the ON position and verify no propane odors near the furnace area. Wait 2-3 minutes for any residual air in the propane line to clear before attempting ignition.

Step 7: Test Furnace Operation and Verify Complete System Function

Set your RV thermostat to HEAT mode at 72°F and listen for the blower motor to activate within 30 seconds, followed by the igniter clicking sound and propane ignition within 5-10 seconds. Allow the furnace to run for at least 10 minutes, confirming warm air flows from all vents and that the furnace cycles off properly when the set temperature is reached. Finally, activate your propane/CO combo detector alarm to confirm no combustion byproducts are present in the coach interior, indicating a safe, properly sealed installation.