Jayco Greyhawk – Furnace Igniter & Control Board Replacement

Jayco Greyhawk – Furnace Igniter & Control Board Replacement

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

Parts & Tools You’ll Need

Step 1: Diagnose Furnace Ignition Failure

Start by listening for the furnace blower motor to engage when you turn on the heat—if it runs but produces no flame after 10-15 seconds, you likely have an igniter electrode or control board issue. Use your digital multimeter to check for 12V DC power at the igniter electrode connector; if voltage is present but the electrode won’t spark, the igniter needs replacement. If there’s no voltage at all, the circuit board has failed and requires replacement.

Step 2: Disconnect Power and Propane Supply

Turn off the RV’s 12V DC system at the main battery disconnect switch, then shut off propane at the tank valve by turning it clockwise until snug. Wait 5 minutes to allow any residual propane in the lines to dissipate, and verify the propane/CO combo detector shows no readings before proceeding with the repair.

Step 3: Remove Furnace Access Panel and Inspect

Locate your Jayco Greyhawk’s furnace access panel (typically on an interior wall near the floor) and remove it by unscrewing the 4-6 Phillips head fasteners. Take a photo of the wire connections to the igniter electrode, sail switch, and control board before disconnecting anything, as you’ll need this reference during reassembly.

Step 4: Disconnect and Remove Igniter Electrode

Unplug the spade connector from the igniter electrode terminal, then locate the single mounting bolt (usually 1/4-inch) that secures the electrode to the furnace combustion chamber. Remove this bolt and carefully slide the electrode out—be gentle to avoid cracking the ceramic insulator, which is fragile. Note the electrode’s gap distance (typically 3/16 inch for Atwood units) before installing the replacement.

Step 5: Replace Control Board and Sail Switch

Disconnect all wire harnesses from the old control board by gently pulling each spade connector straight outward; you may find 4-6 connections including the igniter, blower, and sail switch circuits. Unbolt the old board from its mounting bracket using a 3/16-inch socket, install the new control board in the same position, and reconnect each wire harness in the exact order shown in your reference photo. Test the sail switch (a small lever-actuated switch that detects airflow) by pressing it gently—it should click distinctly if functioning properly.

Step 6: Install New Igniter and Secure All Components

Insert the new igniter electrode into the combustion chamber mounting hole and tighten the securing bolt to 12-15 inch-pounds (snug but not over-tightened, as excessive torque can crack the ceramic). Reconnect the electrode spade connector, then double-check that the high-limit switch (a thermal safety device mounted near the heat exchanger) is secure and making good electrical contact. Close the furnace access panel and secure all fasteners.

Step 7: Test Ignition and Verify System Operation

Restore propane supply by turning the tank valve counterclockwise, then turn the RV’s 12V system back on and set the thermostat to heat mode. Listen for the blower motor to engage (you should hear it within 30 seconds), then watch for a spark at the igniter electrode followed by a steady flame within 10-15 seconds—if ignition fails after 3 attempts, the control board may still be defective. Let the furnace run for 5-10 minutes, confirm warm air flows from vents, and verify your propane/CO combo detector shows no alarms before confirming the repair is complete.