I've been battling with the electrics.
After connecting everything up, the head + tail lights would not work.. at all.
At first, I did not notice that the back also did not work, so initially I investigated the bunch of wires below the dash, as thats where I made the most recent changes.
The lights only switch on when the bike starts.. so each time, I had to:
1 fit tank onto frame
2 reconnect the tank
3 start the bike
4 Check if lights work
At some point, I noticed the tail lights are also not working so I checked fuse #2, but that was still fine.
After going through the wiring harness (as I also made some change there), I still found no obvious issue.
This then directed my attention to the relays in the airbox.
I removed all of them, tested each one.
Each relay also functioning as expected
At least by this time I realized that I could bridge the relay output to avoid having to start the bike each time and by doing so, I managed to get the lights to function. -so it's either a faulty relay or the input to the relay.

I did notice minor damage to the one wire which is supposed to activate the relay for the lights, but thats only to the insulation.

At this point I was out of ideas and the only thing still left to do was to open up the entire wiring harness, but before doing so, I decided to just swap the relays around and ta-da! it works.
Buttoned it all back up:




I'm still confused as to why/how it stopped working.
Post Merge: 21-12-2020, 22:28
ff een update vanaf Radegarage:
RG:
" truth is that some customers have contacted us recently with similar difficulties during the installation.The main reason is, that the shape of side panels has ben designed for bikes with 15lt. tank. Nevertheless, the side panel should be slightly trimmed where it obstructs the front fender in full lock (see the picture), and same with the boreholes dislocation. Please, set the basic alignment with one or two holes and the rest needs to drilled. Surely, we are prepare to compensate your inconvenience with the installation. Please let me know, what amount we should sent you as the partial refund."wolfSkaap:
"...I am wondering if it won't be easier for me to make the 2020 side cover fit the 2017 tank, than reshaping the 2017 side covers with 2020 screen?How about rather than a partial refund, you send me the 2020 side covers (of course, once you have stock)?"RG:
"Yes, we can try it this way. 2020 side covers are in stock, we will send them to your address. For sure, they will nicely fit to the windshield, however not so nicely to the tank. But let’s have a try.My colleague Monika will send you side panels for FE 2020."Vond ik heel aardig van Radegarage