M900 - Electrical Issues When Headlight On

[Jam911]

All the electrics work fine on my bike (M900)

...until I turn on the headlight and then the rear indicators and brake light stops working properly and the instrument display dims.

I am not sure what is going on.

I think it could be a bad earth and wondered what everyone thought or if they have had the same issues.

[Darkness]

All the electrics work fine on my bike (M900)

...until I turn on the headlight and then the rear indicators and brake light stops working properly and the instrument display dims.

I am not sure what is going on.

I think it could be a bad earth and wondered what everyone thought or if they have had the same issues.

Is it fine until you switch on main or dipped beam?

If it’s working fine with sidelights, I would suspect your generator isn’t producing the extra power to run the headlights as well.

Sounds like a session with the multimeter is in order to check outputs and resistances, but a visual check of cables first may reveal corroded connoctors and/or melted cable insulation.

Cleaning or renewing the earth leads is never a bad idea too!

[Mr Gazza]

I wouldn't be so quick to point my finger at the charging system (alternator or reg/rec) as you don't say if this happens with or without the engine running?

With every new re-build it's all too easy to optimistically bolt an earth lead down to a freshly painted or powder coated surface and get perfect insulation!
I would be starting by tracing the rear loom earth back to it's earthing point.

Thinking about it, it's probably more likely that the headlamp is robbing the rear loom of a live?

[Jam911]

Thanks for the posts.

The issue is when either the side or headlight is switched on.

And engine running

[Jam911]

" Thinking about it, it's probably more likely that the headlamp is robbing the rear loom of a live? "

This is what I suspect...but how do I fix it?

[Darren69]

I wouldn't be so quick to point my finger at the charging system (alternator or reg/rec) as you don't say if this happens with or without the engine running?

With every new re-build it's all too easy to optimistically bolt an earth lead down to a freshly painted or powder coated surface and get perfect insulation!
I would be starting by tracing the rear loom earth back to it's earthing point.

Thinking about it, it's probably more likely that the headlamp is robbing the rear loom of a live?

I would say that too, frame and engine have both been painted recently. Check your battery too, it sounds like the headlamp is taking all the smoke.

[Jam911]

I am going to check the rear loom first...sorry but where do I start ?

[Mr Gazza]

Guessing here.. The thing that connects the headlight and the rear loom is the tail light, which should come on with the headlight and sidelights.
So there could be an erroneous connection to the headlight switch, of the cables running the tail light and also stop and indicators.

It could be just a matter of studying the wiring diagram with particular focus on the tail light to switch connections and work outwards from there to the stop and indicator feeds checking that all is connected as it should be... Probably two cables swapped over somewhere?

In the absence of a wiring diagram you could check that the same colour cables are emerging both sides of connectors by tracing the rear loom forwards.

Say hello to tedium.. :mand:

[Darren69]

Doesn't the earth point live behind the rh footrest on those bikes? The rear loom on mine run down the right side of the frame behind the side panel. So that might be a good place to look.

[Jam911]

Thank you very much for all the advice.

I have looked and have decided to book in with a bike electrician instead of poke around myself....in the meantime the LC will come out ...



https://live.staticflickr.com/65535/51142968063_cff52b0075_z.jpg (https://www.flickr.com/gp/192671293@N07/97Qi6o)177688742_143692757727010_98011442644140844 2_n (https://www.flickr.com/gp/192671293@N07/97Qi6o) by James Green (https://www.flickr.com/photos/192671293@N07/), on Flickr

[motomartin11]

Thank you very much for all the advice.

I have looked and have decided to book in with a bike electrician instead of poke around myself....in the meantime the LC will come out ...



https://live.staticflickr.com/65535/51142968063_cff52b0075_z.jpg (https://www.flickr.com/gp/192671293@N07/97Qi6o)177688742_143692757727010_98011442644140844 2_n (https://www.flickr.com/gp/192671293@N07/97Qi6o) by James Green (https://www.flickr.com/photos/192671293@N07/), on Flickr

Ver nice
Used to have one like that myself but I sold it in 2015 to put towards a sports car.

[Jam911]

Getting slightly bored with my on going electrical issues....

...rear break light not working is to be added to the list for my electrician.

The list currently is :

No rear break light from foot pedal ( works fine from front lever)

No rear indicators / brake light when headlight on

No "indicator on" light on dash when headlights on.