Electrical gremlins

[jamestnewsonr65]

So I took the bike out for a run yesterday and noticed that since the last time it had been out the rear light and brake light had stopped working. Everything has been perfect for the past year so not sure whats happened.

After a bit of investigation yesterday it seems that it is something to do with one of the items on the same circuit.

Ive taken some pics of what is happening at various points (below) and have taken a couple of videos to show what is happening also.

The bike is running fine so the problems only seem to effect the external electrical items on the bike. It's also connected somehow to the switching of the ignition as in certain circumstances the indicator relay triggers and switches the rear light on and off.

It is a little hard to explain what is exactly happening but hopefully these images and explanations will give enough indication that someone might be able to help me diagnose the problem.

Image 1:

Key position - Off
All as it should be.


Image 2:

Key position - 1st
Bike switched on
Rear light - Off (Should be on)

Image 3:

Key position - 1st
Bike switched Off - The Acewell comes on but should be off as nothing should happen but the side lights come on.
Rear light - Off

In this position, if I turn one of the indicators on, it starts to trip the relay and the rear light flashes in time with the relay. It also trips the Acewell on and off. (See the videos below showing what happens and you can hear the relay tripping)


https://youtu.be/ncOI1XseE4E

https://youtu.be/DrbaKbE4IWc


I've tested some of the wiring with a voltmeter but to be honest i'm not really too sure how to go about diagnosing where the problem is originating from or how to fix it. It would seem logical that maybe there is a problem with the live supply to some of the bike.

Any pointers here would be gratefully received as im at a loss and might have to get a motorbike electrician to look at it.

[thrang]

Is the wiring loom stock James?

It's kind of hard to see what you have from the photos.

I'm not great at ellecy, but I have always managed on an R65, so what I'd do is check if I have power to the brake/tail assembly, if you have power but no light, bad earth. If no power when indicator on (think what you have) separate out the two circuits and do a cont test between each and see if you can narrow down where the indicator is interfering- probably round the rear main block socket but that's a guess.

With out knowing exactly how you have modded the loom the its hard to punt a suggestion past the above.

[jamestnewsonr65]

The wiring loom is all standard apart from where the Acewell wires were soldered into the original wires.

I measured the volts at the rear light connector and get 12.7v on both the green and grey wires (Brake and Tail light), 0v on the brown.

When the indicators are tripping the rear light I get a measure between 12.7v and 0v as it triggers the relay.

Thinking I might have to strip the loom back and just check all the connections. Not a job i'm looking forward to.

[nhmaf]

Are you certain that you didn't accidentally create a short between some wires when you patched in your speedometer?  It sounds as if the relay is doing what it is supposed to be, but perhaps one if its wires is getting connected to ground or switched power to activate it when it should not be?

[jamestnewsonr65]

Im pretty sure I haven't created a short as everything has been working perfectly for just under a year now.

Will do some more investigation today and if I cant source it I may just strip it all out and try to find the fault.

[jamestnewsonr65]

I tried to figure this one out again today but no joy.

I've inspected each of the electrical connectors and tested each one to see what effect it had on my problem. If I disconnect something on the offending circuit like the rear light, front brake switch, horn etc then things start to act as they should but without the rear lights.

This seems to indicate that it is definitely in the loom somewhere with a shorting wire or something similar.

Has anyone built up their own looms? Something I know nothing about but it can't be that hard using the existing as a template or guide.

[Bob_W]

For weird electrical problems the ground is always suspect. When you measure 12.7 volts on the tail light what do you use for the meter's black wire connection?
Try from a known positive such as the plus side of the battery to the brown wire at the tail light.It should also read 12.7 volts.
If there is voltage on one side of the bulb and a ground on the other, the bulb will light unless it is burned out.

Bob

[jamestnewsonr65]

I was using the negative terminal for the black wire connection.

When I use the positive terminal on the plus side of the battery I still get 12.7 volts.
One of the wires in the fitting was very loose and the solder to the fitting had come away. Even when sorting this out it still didn't work.

After testing the bulb with an open circuit on the multimeter, I get an amp reading on one side (Brake light) but nothing on the side light. Going to get another bulb and see if this improves anything. Probably not, but worth a try.

[jamestnewsonr65]

Finally managed to track down the problem. As the Ohm test on the bulb showed it was toast and fitted a new bulb which worked and fixed it all.

Sometimes the simplest things seem to cause a bit of a headache, especially when your not technically minded.

[montmil]

...noticed that since the last time it had been out the rear light and brake light had stopped working. Everything has been perfect for the past year so not sure whats happened.

Any pointers here would be gratefully received as im at a loss and might have to get a motorbike electrician to look at it.

POINTER #1: Always check the simple stuff first.

[Ed Miller]

No help to you, but that is a clean installation of that speedometer and that whole area.  I should re-do mine, you know, one of these days.