Wiring meltdown..

[GSmiles]

The dip beam bulb had failed, so I bought a new one, and pulled the old one out of the lamp unit...the connector had gone into meltdown.

The brown wire has actually gone black and the core has deteriorated.I got a fresh connector from a scrap car headlamp (free from a local repair shop), cut the wiring back as far as I could, trying to find undamaged core in the wire, fitted new spade terminals in to the secondhand connector and everything seems fine now. Has anybody else had this kind of meltdown? Or have any good ideas about why it happened. If it happens again its going to get boring as the headlamp unit seems to be absolutely glued into one piece, and it'll be, er, interesting trying to replace the wiring through the bulb apertures......there is no slack left in the loom now.
My bike is from May 04, has 68000kms and usually goes just great. There has been one oil seal failure on the outside of the rear hub (the easy one...at 65k (kms), and apart from the treatment received ( by myself and by the bike) at the main dealer where I bought it, I am a happy little GS rider, generally to be found storming up and down the mountain roads where I live, expecting my bike to last forever..............

Here is a picture in its new black paint on Saturday afternoon just after I finished putting it back together......Once I had pulled the headlamp unit out in order to fix the wiring, I decided it was time for some fresh make-up and gave the beak and the tank panels to the friendly local car repair shop on Friday morning, picked them up on Saturday, and hey presto...New Bike.

 

[GSmiles]

Oh, will it work this way?

Can't get the photos uploaded, damn, I hope the repair works rather better..

 

[ELIMINATOR]

NO

 

[snoopy]

The core will normally deteriorate it's the copper oxidising.

 

[GSmiles]

Yes, although the melted state of the black connector that the bulb plugs into is not at all normal......shame I can't seem to do the photo upload thing....

 

[Magwych]

Hi GSMiles, and welcome.

It sounds like something has been shorting out, if the connector has melted, but the CANBUS should have detected the higher current and switched off the circuit. Th eshort could have been the bulb retaing clamp, it is notorious for coming away from underneath the little screw that barely restrains it.

Give up trying to post pictures, you need to be a site subscriber to do that - or join up and post away?

BTW, I recall your part of the world, I have spent many a happy moment down in El Colmenar/Estacion De Gaucin on my old R100T... I would guess it has changed a lot since the late eighties.

 

[GSmiles]

Ok,Ok you've all paid up, so I have as well...
So, here is what the connector looked like....
And a picture of the bike.
And yes, I too thought that the Canbus was supposed turn the current off when faced with the additional load of melting the connector and it's wire...
Couldn't see any traces of arcing or blackness on the bulb retaining clip...but maybe it was just that.
Hey CityBum, some things have changed around here since late 80s, but the roads still have more curves than straights, and some of them even have decent surfacing nowadays..! Weather is still good too.....

 

[alimey4u2]

May not have been a high current failure but a poor connection either to the spade or the bulb generating heat....

 

[shugie]

May not have been a high current failure but a poor connection either to the spade or the bulb generating heat....

Possibly some of the cores of the stranded cable had failed where they joined the connector, and the cable has been overheating at that point, although the canbus should have "seen" the extra resistance and given you a bulb fault I would have thought.

I'm none too sure about how accurate the canbus protection is.

 

[alimey4u2]

Possibly some of the cores of the stranded cable had failed where they joined the connector, and the cable has been overheating at that point, although the canbus should have "seen" the extra resistance and given you a bulb fault I would have thought.

I'm none too sure about how accurate the canbus protection is.

I would agree on all accounts....

 

[T900]

make sure you have the correct bulb rating fitted as some people tend to fit higher wattage ones to increase the lamp output, for example you have a 55w fitted not 75w or 100w .
the higher output bulbs draw more current, thus creating more heat leading to the connector melting and the wiring oxidising . if the correct bulbs have always been fitted, then the connector may have been weakened at some stage. the can bus will only sense a complete open circuit (blown bulb) or a complete short circuit.
hope this helps.

 

[GSmiles]

Thanks for the comments guys,it does seem likely that the connection had become imperfect, and that the extra resistance built up and caused the meltdown.The bulb was the standard rating, and the canbus did finally report a bulb failure, but only because the bulb had given up the ghost. It is interesting to learn the limitations of the canbus system, and interesting to realize that BMW actually refined the wiring cross section to the minimum possible. I hope it doesn't re-occur, as there is now no slack at all in the wiring and changing the wires would be an interesting challenge- the glass is bonded on to the headlamp shell and the only way in is through the bulb mounting holes. And a new lamp is not cheap...
Oh, by the way..my bike uses one low beam bulb per 10,000miles- is that the same for everyone ?

 

[The Bede]

Oh, by the way..my bike uses one low beam bulb per 10,000miles- is that the same for everyone ?

... How do you get them to last so long?


... FWIW, I suffered a similar 'meltdown' on my 06 GS.
...When I got the can-bus warning it explained the burning smell I'd encountered a day earlier