Instrument lights goes out when high beam is activated

[cda]

Hi, I have a -02 V11, LeMans, my problem is that when I activate the high beam the instrument light goes out.

Otherwise with low beam on, they works fine.

The city light is out as well and I have changed the bulb with no luck.

These faults have been present since I bought the bike, everything else seems to work fine.

 

Is there anyone out there, who recognize these faults??

Could it be the headlight switch,  a relay, short circuit or what, the circuit diagram just confuses me.......

 

Every information of where to start the troubleshooting welcome :-)

[footgoose]

welcome cda! I am not the electrician here but there are several members who are. Just to be clear, what 'instrument light' goes out? And, sorry but which is a city light? There's loads of info here concerning the often problematic dash lights. I suspected corrosion in my dash lighting, and cleaned sockets and replaced all bulbs. Next time I'll consider the led option.

[cda]

Ok, thank's!

The bulbs which goes black are the  ones illuminating the speedometer and tachometer gauges.  And the "City light " is the 4W bulb- front parking light might also be called dipped beam.

The dash lights are actually still ok, all of them, as far as i know...

[JBBenson]

I have the 4w "city lights" on the Hella driving lights I mounted on my BMW.

 

They are more like "parking lights", NOT a dipped beam, which is the same as "low beam". 

[cda]

Thank's for the info it might be so it works with the parking light, but that is the minor problem.

Only mentioned if it has something to do with the main problem. That bulb is mounted on the a cable running to

both the gauges. And shares the same ground as the high and low beam lights.

 

Anyway the big thing is the gauge illumination that goes black when most needed.

It's a bit difficult when  riding in the dark trying to keep the pace by the sound of the engine:-)

[stewgnu]

Mine went haywire last year- when i took the clocks out i found badly frayed and virtually severed cables. Never got to the bottom of why they were in such a surprisingly bad state. The speedo drive went soon after so i junked the lot and fitted an after-market unit which has been fine.

[docc]

Comes to mind to service all the grounding/earthing. Especially the primary ground cable from battery to gearbox and the regulator case ground to the engine. Also, check and reset all the fuses and relays. Be certain you are running a full compliment of high quality 5-pin relays. I prefer OMRON, but many are running others, including GEI.

 

Consider cleaning your ignition switch. Be sure your battery is well conditioned.

[Kiwi_Roy]

That is a weird one, the tail light must be going out also.

Narrow it down a bit by checking for Voltage at the fuse 6 on this diagram, check for the correct fuse by pulling the fuse to see if the lights go.

 

If you do have power on the fuse the next place to check is at the handebar switch.

 

Just a note, all those lights are fed from a different ignition switch contact, the wire has been known to break off but I'm leaning more towards the dimmer switch.

[cda]

Thank's a lot for all the interrest in the matter. I will start with the fuse and switch and go from there.

I have plans of disassembling of the dash anyway as it totally disintegrated as I was going to replace a bulb earlier.

Might be good to check the grounds again I will probably remove fairing and tank as well so it might take a while.

I assume the fuse six corresponds to the one with same number at Carl Allisons diagram (and even the original).

 

I'll be back if I find anything of interrest, thanks' again for all valuable hints.

[GuzziMoto]

All those circuits, especially if the tail light is going out as well, are also on the same relay as I recall. If the relay drops, those will all go out. There may be something about turning on the high beam that drops that relay.

[Stick]

Definitely check the rear running element, as Kiwi_Roy mentioned, to make sure it's working or not.  It is on the same ckt. as that front 4w "parking" lamp.

 

But after digging into my gauges for a broken tip of the speedo cable, I was amazed as to how LOUSY the wiring is in there on the gauges.  Most notably, the ground wire attached to speedo and tach.  Very marginal,   I'm surprised that the tach and illumination worked at all.  

 

I had to improvise in there to establish better grounds.

[docc]

Instrument lighting, tail light, 4watt "city" lamp, and license tag light are all Fuse 6 from the ignition switch - no relay.

[Kiwi_Roy]

As Stick mentioned it could be the ground but why only on high beam, I could see it if the headlight was dim.

I would check the headlight wiring and measure the Voltage on the instrument cases reference to the main chassis or a bolt on the engine.

The gauges are insulated from the dash by the rubber grommet.

I'm wondering if the headlight is wired incorrectly and you're getting the two filaments in series on High with the gauge ground at midpoint.

On High beam the gauge ground might be rising to 6 or 8 Volts reference to the chassis.

 

I always get confused looking at the headlight socket so usually end up measuring the bulb to find which is common

Low and High beam connections are the two with the greatest resistance.

 

If the H4 socket shows any sign of heating throw it away.

 

Update:

Another possibility is the gauge lamps are somehow grounded to the high beam filament, they would operate normally on Low Beam but have zero Volts at High Beam.

The tacho would keep working because the electronics has a separate ground.

 

Update: Remember to check for Voltage on the ground wires for the gauge lights and the headlight referenced to a solid ground on the engine.

[cda]

ok, now it seems that I have some things to do. I once had LeMansV and 750Targa, I disassembled the ignition switch on both of them.

That was really needed both switches where in great need of cleaning.

But I don't see that would be the problem in this case I believe that either the high or low beam would work.

So I'll go for the other suggestions, hopefully this weekend

[Kiwi_Roy]

Bear in mind that the bike is in Europe, your wiring may be a little different than the Nth American version.