Thetford N3112 fridge igniter does not always produce a spark

[Furkat]

I started having issues with my Thetford N3112 fridge recently. It stopped working from gas. When I reset it couple of times (random, it can be 1, 2 or 5) it works again. I opened the back cover to troubleshoot and found out that the igniter doesn't produce a spark sometimes. However, I hear the 'click' sound from the controller, which gives me a guess that it tries to send a signal to electrode to ignite the burner. The official Thetford manual says to replace the entire controller, which is pricey for me. Are there other ways to troubleshoot and fix the issue? I was thinking to replace the electrode, but how do I make sure that the problem is faulty electrode?

 

[GeoffnDee]

It could be worth checking that the burner earth is ok also that the spark gap is correct at about 4mm , if the controller was faulty you would normally expect an error code , either on the right hand side of the control panel (if LCD display ) or using the temp. display when in service mode (if LED display)