Not tired of this type of request at all. There were very few B4 920s made and the manual seems to be a bit of a unicorn.
The wiring diagram was supplied with the Owner's Manual if you happen to have that piece of kit.
The most reasonable advice I can give is that it is very similar to the 990 and that wiring diagram may help.
I assume you searched our library and found nothing there.

 

Ive been on a bit of a mission today as my headlight suddenly stopped working. I wanted more light from the headlight so have purchaced a reasonably decent H4 Led, put it in, it glowed but it didn't work. I then put the original bulb back and it didn't work....... I then tested them both on a 12v battery and they work perfectly but not when fitted in to the headlamp unit itself and plugged in. I pulled all the fuses and relays and they all work, checked all the wiring point to point and that all has continuity as it should so I can only think that the switchgear has gone on me. I took that off to test and I can't test that properly as to be honest it's stumped me a little. The horn & indicators work as they should but I ain't spending £125+shipping from Italy for a new one just to see if it is that so i think i'm going to have to bang it in the shop and get them to look it. 😤 If it's gone it's gone but i NEED to know. I can still ride her during the day but being in the northern hemisphere it gets dark at 16:30 at the moment so can't really go too far....... I'd rather suss the issue myself but she has me stumpted at the mo......

 

The fact that the new bulb glowed and then after swapping back the original nothing works tells me you have a high resistance in the wiring. Since the only things disturbed was the headlight bulb connector and/or the headlight to harness connector that is where I would look.
Not much to it. No computer circuitry, no ECM.
The wiring schematic for the lights will be the same as the other Brutales of the year model.

 

Thanks. I don't want to sound dumb or want to seem ungrateful for your reply but why would that prevent the the original halogen bulb working again? If the halogen bulb had blown, i then took it out and relpaced like for like it should just work, no?? So to me the LED bulb i put in has done something to the lighting circuit somewhere to prevent the halogen one working again .... ???

 

The halogen bulb doesn’t work anymore due to the bad connection created when swapping in the new bulb. Look at all the wires and connectors you disturbed. especially grounds.

 

I have a 920 and swapped the original bulb for an LED, had no problems at all apart from useless light pattern. It was bright but lit up nothing. I then got a Halfords extreme bulb and it’s better than the LED.

 

Halfords Advanced not extreme.

 

Sussed......! Thanks for all your suggestions and help on this peeps.... Eventually i've found some time to get back to this issue & I found a cable just under the rear fuses that had the insulation worn away by abrasion and had been shorting out on the relay frame..! Taped it up..... 'et voila'..... I now have LED front lights...!