Thor Outlaw – Furnace Igniter & Control Board Replacement

Thor Outlaw – Furnace Igniter & Control Board Replacement

by

Complete repair guide for the Thor Outlaw – 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 verifying that your Thor Outlaw’s furnace isn’t producing heat, then locate the furnace compartment (typically under the dinette or bedroom area). Use your digital multimeter to test for 12V DC power at the furnace control board connector—if voltage is present but the igniter electrode isn’t glowing red when the thermostat calls for heat, you’ve isolated the problem to either a failed igniter electrode or a faulty control board. Document which components are non-responsive before proceeding to removal.

Step 2: Disconnect Power and Propane Supply

Turn off the main 12V DC battery disconnect switch and shut off the propane valve at the tank exterior—never work on furnace components with active power and fuel supplies. Wait 5-10 minutes to allow any residual pressure in the propane lines to dissipate safely. Verify the propane valve handle is perpendicular to the supply line, indicating it’s fully closed.

Step 3: Remove Furnace Access Panel and Old Igniter

Locate the furnace access panel (secured with 2-4 Phillips or hex-head screws) and remove it carefully to expose the burner assembly. The furnace igniter electrode is a ceramic-tipped probe positioned near the burner nozzle; disconnect its wire connector and unbolt it from its mounting bracket (typically a single M4 or 1/8-inch bolt). Note the electrode’s exact position relative to the burner flame pattern for proper reinstallation of the replacement.

Step 4: Replace Igniter Electrode with New Unit

Install the new furnace igniter electrode by threading it into the mounting bracket at the same angle as the original (typically 30-45 degrees toward the burner nozzle), then torque the bolt to 2-3 foot-pounds to avoid cracking the ceramic tip. Reconnect the igniter wire, ensuring the connector is fully seated and the wire isn’t kinked or routed near hot surfaces. The electrode tip should sit approximately 1/4 inch from the expected flame pattern.

Step 5: Remove and Replace Furnace Control Board

Locate the furnace circuit board mounted on the side of the burner box; disconnect all wire harnesses by gently prying the connector clips with a small flat-head screwdriver. Remove the 2-3 mounting screws holding the board and carefully slide it out, noting the orientation of any ground straps. Install the new furnace control board in reverse order, ensuring all connectors are fully seated and the board is mounted with proper ventilation clearance (minimum 1/2 inch on all sides).

Step 6: Verify Furnace Sail Switch and High-Limit Function

Check that the furnace sail switch (a spring-loaded flapper that detects blower airflow) moves freely and isn’t stuck with dust or debris—clean gently with compressed air if needed. Test the high-limit switch by using your multimeter in continuity mode; it should read continuous resistance below 120°F and open above 130°F when heated with a heat gun (do not exceed 150°F). Both switches must function correctly for the new control board to operate safely.

Step 7: Test System and Confirm Safe Operation

Restore 12V DC power and propane supply, then set your Thor Outlaw’s thermostat 5 degrees above the current temperature to trigger a heating cycle. Listen for the igniter electrode to click and observe it glowing orange-red within 5 seconds; the burner should ignite within 10 seconds and the blower motor should activate after 30-45 seconds. Verify your propane/CO combo detector remains silent, confirm heat is reaching the living space within 2-3 minutes, and monitor the furnace for 15 minutes to ensure stable operation without flame-outs or unusual sounds.