Strange issue. Headlight goes out and abs light comes on

Yes it's the brake light that comes on and stays on. WTH..

So the Horn/Indicators stop working but brake light stays permanently on regardless of any brake switches being pulled. Turn off the ignition with kill switch earth the brown wire and needles sweep and brake / tail light work as normal. While it's in the fault condition, headlights/park lights/high beam work as per normal.

So I'm going to get it into the fault condition then have a play around with the loom while it's in that state. Any tips to look at first? Fuses to pull, wires to check for voltage on?

I just dont see how that brake light can be lit unless its connected to something else
Are you confident you have the running, brake & ground all wired correctly to correct OEM wires pin for pin with your rewire mod?
And there is no chance of anything shorting inside the light housing?

Incidentally is wiring from box original again or are blue & orange swapped? (Still doesnt explain why brake element is on, but want to understand if same keyless channel is tripping as before, but if now the outputs for brake/turns/horn are swapped with lights)

Can you do a test run in daylight tomorrow with rear light completely disconnected?

Hi Ken. Yes I've checked and metered out the rear lights I rewired. The wiring from the box is the correct way around. I didn't swap the orange and blue, so it is the other channel than what was tripping before, now tripping this time. I'll try a run with the rear light disconnected. Where would be best to disconnect it from? The plug behind the right hand panel or somewhere further into the loom?

So in theory when it trips now does it stop sending power out on the orange wire? So if I disconnect the orange wire in the bike side where it is a bit easier, wouldn't that stimulate the same issue and i can see if the brake element is still lit.

Yes, the orange circuit is what is currently tripping (the blue one before)
No need to disconnect the orange - if it's tripped the brake light power cannot be coming from there regardless, since it has to go via either of the two brake switches to get to the lamp.
The brake light (common output from the two switches and to brake light circuit element) is also connected to the ABS Module - but that would be an input (to tell the ABS module when brake is actually being applied) and I can't see any scenario whereby the orange circuit being out would apply power OUT of the ABS module to the lamp

The orange circuit is directly connected to
The Horn
The Turn Signal Module
The Input Pole of both Brake Switches

The Brake Light is connected to
Each of of the Output Poles of the Brake Switches
The ABS Module

When the brake switches are not made, then no current flows from the Orange circuit to the Brake Light
When the Orange circuit is tripped, obviously no current can flow from it, especially through 'open' switches
Which begs the question, could it be getting power OUT of the ABS module?
Well why would it? The ABS module is clueless that the Orange circuit has tripped right? There is no connection from Orange circuit into the ABS or any other related components - and the brake light input to ABS is no different than if the brake switches were simply not 'made' i.e. open. So what could possibly trigger the ABS to OUTPUT voltage to the brake lamp? It seems unlikely

It is odd. Thanks for your patience Ken.

I was looking at the schematic last night too and came to the same conclusion. Unless there is power coming *out* of pin 4 on connector 45 (ABS) how can it be lit!

I'll see if i can get it into the fault condition, get it back home, and have a look into it. I'll see if the fault condition continues with engine not running, like if I stall it, cos it would be easier to do it all without the engine running.

Hi @DEcosse More investigation. I'm actually doubting myself now that it was the brake light I saw lit previously. Although I thought it looked bright enough to be brake light, i didn't actually check with more than a glance, i didn't check which wire to the back twin bulbs was live. While the turn/horn/brake circuit still keeps tripping out with no rhyme or reason for it to do so, brake light defo isn't lit, just the tail light. I've gone back to using the keyswitch too and no fuses are blowing. Worked fine over 2 hour test today (essential journey).

Martin-Brighton-uk said:

Hi @DEcosse I've gone back to using the keyswitch too and no fuses are blowing. Worked fine over 2 hour test today (essential journey).

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So you disconnected the keyless system and basically reverted to stock and the problem went away?

Stillserving said:

So you disconnected the keyless system and basically reverted to stock and the problem went away?

Click to expand...

Correct.