Hello Mark, my name is Jeff.
You are correct in stating that there are no longer pilot lights on the furnaces. They are what is called Direct Spark Ignition. That is the clicking that you are hearing, it is the ignitor trying to light. If the ignitor is trying to light but you have no gas to the burner, then that is the problem. You could have a bad board or a bad gas valve. You can remove the board and have it tested at any RV Repair facility. You could also have mud daubers on the burner assembly causing it not to light. In either case, you will need to either pull the furnace or open the outer cover (depending on the model of the furnace). If you have an atwood or hydroflame, then you can easily open the outer cover and remove the board. If it is a suburban or duo-therm then the entire furnace will need to be pulled so you can access the internals. I hope this helps, if you have any further questions or concerns then please let me know and I will help you through. If you need further assistance, please provide me with the model number and make of the furnace.
If this helped, then please hit the accept button so that I can get credit for my efforts.
Regards,
Jeff Myers
On the Atwood Model 8531, the board and the burner assembly are accessible through the front panel. Remove the front panel and the board is located on the left hand side of the unit and is easily removeable by removing the wingnut and pulling the board out. You can then have it tested and checked to see if it is ok. The burner assembly is on the right hand side where the propane line comes in. That is also where the gas valve is located. Shut off the propane and remove the line from where it comes in. There are 1/4" screws that attach the gas valve/burner assembly to the back wall. Remove these screws and the entire assembly will come out. Check the ignitor assembly to make sure it is clean and check the burner assembly for cleanliness. This sounds like it may be the problem and should fix you up.
Let me know if you have any other questions or concerns.
If this works, hit accept so that I can get credit for my help.
RV Mechanic
Owner of an RV Repair Facility for 9 years. 12VDC and 120VAC, ALL Appliances, Any and ALL problems!