A furnace that clicks but will not light has already passed some early steps: the thermostat called, the blower ran and the control board attempted ignition. That narrows the problem.
Do not keep cycling it endlessly. Repeated failed ignition can create odor, lockout and unsafe conditions.
Confirm safe propane supply
Make sure propane cylinders contain fuel and valves are open slowly. Establish a steady blue flame at the range, then turn it off. If every propane appliance is weak, focus on supply, regulator or lockout before the furnace.
Reset lockout correctly
After failed attempts, many boards lock out. Turn the thermostat off long enough for the manual’s reset procedure. Record any flash code before removing power.
Listen for the sequence
- Blower starts.
- Airflow proves through the sail switch.
- Ignition clicks.
- Gas valve opens.
- Burner lights.
- Board proves flame and keeps running.
If it clicks but never lights
Possible causes include no gas at the furnace, low gas pressure, obstructed burner, electrode position, weak spark or board/gas-valve trouble. Owner checks should remain external: battery voltage, propane supply and vent blockage.
If it lights then shuts off
A brief flame followed by shutdown often points to flame sensing, grounding, board, electrode, gas pressure or burner condition. These are combustion-system checks for qualified RV propane service.
Keep troubleshooting
Use these related RV Solver resources to narrow the problem and avoid parts guessing.
When to call a professional
Use qualified service for gas-pressure testing, burner removal, electrode adjustment, gas valve diagnosis, combustion chamber inspection, soot or repeated ignition failure.
Sources and editorial notes
RV Solver pages are written for practical owner education, then safety-edited for common electrical, propane, water, roof, appliance and towing risk points. Always confirm procedures with the manual for your exact RV and installed component. See our editorial policy.