Until I know the serial number of your system, I am not sure if your gauge version.
Qestions:
1. Does your have have a RJ-45 socket at the back or a 2.5M trailing black cable
2. The flicking is not not be due to the RJ-connector. The earlier version of the DDS3v10 board is sensitive to noice at the +12V supply. Anyway, this is gone with the new cable.
3. I think we should fix the cable problem first (the new one).
It is quite easy to have a partial short between the strands of the flat black cable, could be badly crimped or flexed too much during installation.
Anyway, perhaps it is better to make a new cable, just cut off the two plugs and crimp on new once. Make sure the plug/plug orientation is as following (colour is not important)
And check for damages:
