Norcold refrigerator "NO FL" code, propane burns fine

Thanks guys for guiding me. I have replaced the spark wire yesterday. The sparks work GREAT and the flame starts every time.

However, despite that, flame is still NOT detected.

The "tower" on top of the control board, from where the spark electrode terminal comes out, is NOT loose.

I feel that I am making progress, eliminating possibilities at acceptable cost, but still no final resolution.