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2011 RT1200 left low-beam headlight failure

srmRT

New member
As the title indicates, I had just pulled into my dealer's lot when I looked at the reflection in their front window and noticed the LH low-beam headlight was not burning. After determining that the LH low-beam was definitely not functioning as designed, I asked the service manager about replacing it while I was there. She quoted me a very reasonable price for what should have been a quick replacement so I decided to do it. Long story short, the tech installed a new bulb which did not work because he found no power to that light socket. The filament in the "old" bulb was good and not failed. Further investigation would have involved more time, and it was late in the day, so we decided to schedule another service appointment to check it out. The RH low-beam still works, as does the hi-beam.

The bike has 29,000 miles on it, has been well-maintained, and is very clean. I did install a Denali Cansmart system on it about four months ago, with only a set of fender-mounted DRL's on the front, and all headlights have worked fine with that system until yesterday's failure of the LH low-beam.

Any ideas about something simple/obvious I might check on my own? I know it could be a bad short, broken/loose wire, or some other typical electrical gremlin. My Haynes manual's electrical schematic shows a couple of fuses going to what looks like headlights, but I cannot tell if that set-up is for an RT or not.

Any help will be greatly appreciated. Thanks.

Steve
 
The socket the bulbs plug into are known to fall apart and a potential for failure. The plastic used degrades over time becoming brittle. I replaced them with ceramic ones.

There is a harness that plugs into the back of the housing, maybe that connection is faulty. From there it probably is controlled by CAN BUS.

Sent from my Pixel XL using Tapatalk
 
The socket the bulbs plug into are known to fall apart and a potential for failure. The plastic used degrades over time becoming brittle. I replaced them with ceramic ones.

There is a harness that plugs into the back of the housing, maybe that connection is faulty. From there it probably is controlled by CAN BUS.

Sent from my Pixel XL using Tapatalk


Thanks for the info. I "assume" the socket was intact, as that would have been obvious, and the tech did do a little more troubleshooting
after seeing that the new bulb did not work. He suspected some problem in the wiring going to that light but did not want to spend a lot of time on it without my authorization for the additional charges it would have entailed. You are correct in that, provided the socket is not deteriorated, the problem could be anywhere in that light's wiring harness. I will try to get it apart to where I can fool with the harness/connector/plug and see what gives. I would think that if the problem is with the CanBus system, then both low beams would be affected. But what do I know! :)

Thanks for the help, and where did you get any ceramic replacements?
 
srmcteer - did you not have a bulb out notification on the dash? (little bulb with an arrow pointing forward)
 
You can survive just fine with no plastic or ceramic surrounding the metal female connectors and failure of either does not cause the electricity to stop. It's simply insulation and protection to head off the two wires contacting each other ... which they will not do connected to the bulb and to the headlight housing. The problem is elsewhere.
 
srmcteer - did you not have a bulb out notification on the dash? (little bulb with an arrow pointing forward)

I did not have one the day before on a 150 mile day. I did not notice a notification on the dash as I rode to the dealer, which is only about 15 miles, although on a sunny day the dash is hard to read and I don't know that I was paying that much attention to the dash on the short trip up through town and traffic to the dealer. However, upon getting back on the bike after the service work, I did see the little bulb indicating a failed bulb. I see it now but for sure did not see it the day before discovering the problem.
 
You can survive just fine with no plastic or ceramic surrounding the metal female connectors and failure of either does not cause the electricity to stop. It's simply insulation and protection to head off the two wires contacting each other ... which they will not do connected to the bulb and to the headlight housing. The problem is elsewhere.

Probably so, somewhere in the plug/connector/wiring harness, who knows? I see it is not too hard to get into the back side of the LH low beam, so tomorrow I will get into it and see what I can find.

Thanks for the insight.
 
I did not have one the day before on a 150 mile day. I did not notice a notification on the dash as I rode to the dealer, which is only about 15 miles, although on a sunny day the dash is hard to read and I don't know that I was paying that much attention to the dash on the short trip up through town and traffic to the dealer. However, upon getting back on the bike after the service work, I did see the little bulb indicating a failed bulb. I see it now but for sure did not see it the day before discovering the problem.

Okay - that's actually a good thing (that you're seeing the dashboard indicator). If you weren't, that would tell us that somewhere along the line, the CANBUS system is not detecting a fault with the front light.
 
Okay - that's actually a good thing (that you're seeing the dashboard indicator). If you weren't, that would tell us that somewhere along the line, the CANBUS system is not detecting a fault with the front light.

Excellent thought, thanks for pointing that out. I watch my gauges pretty closely while riding and the fault indicator was not on the previous day.

So the CANBUS system seems to be working properly, as you point out, which is a good thing. With a nine year old bike electrical gremlins are entirely possible. Oh well, it could have been a failed FD, or an ABS pump, or some other $$$$$ problem. :)

I appreciate your input! :)
 
I looked closely at the "old" bulb that was in the bike when the LH lo-beam went out, and I think the two posts on the back are arc'ed across at the bases, which I guess would have caused the bulb to fail. I am in the process of removing body work to I can access and inspect that terminal/socket better, hopefully tomorrow morning. I will also pull the "new" bulb the tech installed and see if it also arc'ed across the base after he installed it, since it would not fire either.

If that is the problem, then it seems the cure will be a new socket, such as several responders to this thread referenced. Splicing a new such socket into the existing wiring going to that socket should not be too difficult for a good mechanic, provided he can gain access.

I bought the bike from a retired Marine Corp aircraft mechanic, and he has had numerous bikes, mostly BMW's, over last many years, and is as good a mechanic as one could find. Given his experience with bikes and other much more complicated contraptions, I think he can rectify my problem in short order, provided my preliminary diagnosis proves to be correct.

Thanks for all of the most helpful replies, and hopefully my problem is not as serious as it could be and can be fixed relatively easily. :)
 
Mike,

Thanks for the links, and I have seen some other tutorials as well, and it is not a big deal. I took the side panels off last night, an easy task, and will get into the rest of it this morning. From what I see, one set of the replacement ceramic connectors just requires un-crimping the old OEM connector from the two wires and then crimping the wires to the new connectors which then plug into the back of the new plug. I think another set of replacements referenced have wires already attached and would probably require splicing them into the OEM wires. I think I would prefer the first solution, given my druthers.

Now would probably be a good time to check the other connectors and replace them--and the 9 year old bulbs--with new ones. I would rather ride than work on bikes!

Thanks again for the input and the links, I appreciate it! :)

Steve
 
I have found the plug for the failed LH lo-beam to be intact and it does not appear to be damaged. The new bulb also appears intact. As the tech discovered, there is no power coming to that plug after the failure of the "old" bulb, hence the new bulb won't fire.

If the old bulb corroded and shorted across the two contacts at the base, causing a failure, would this feed back into the ZFE electrical unit and cause that circuit to be non-functional?

When the bulb shorted across the two pins, could that have caused a break in a wire between the bulb and the ZFE, without reaching the ZFE and damaging it?

Provided the first scenario happened and the circuit within the ZFE unit shut down, can it be "reset" electronically (maybe a special BMW tool or dealer's computer) in any way, similar to resetting a circuit breaker or replacing a fuse, once a problem is rectified? If it cannot be, and the shorted bulb caused a failure of a circuit within the ZFE, then I would think that the ZFE is toast and needs replaced.

If the second scenario happened, then a continuity check of the that particular lo-beam circuit between the bulb and the ZFE should determine if the wiring is damaged, correct? And how in the world would one find that damage, except by luck?

My dealer is only 14 miles away, and they are pretty good and have offered to schedule some diagnostic/shop time. I feel sure they can find the problem, given enough time, and I don't mind patronizing them. I am just trying to get an idea before hand of what that problem might be, and to see if there is possibly a relatively logical starting point for troubleshooting. I have the side panels off and don't really feel like pulling the rest of the body work to remove the headlight nacelle, since I think either of the two scenarios I outlined above really require a dealer's experienced hand to rectify and any further effort by me would be a waste of time.

Any help/suggestions will be greatly appreciated. Thanks.

Steve
 
Just to be clear - you've had the bike running while attempting to check voltage at that plug? (no low beam headlights without the engine running)
 
Yes, bike running. RH lo-beam shining, hi-beam shining, LH lo-beam dark as night.

I have made many rail-headed missed-diagnoses in the past, but not this time. :)

Thanks for the input.
 
Yes, bike running. RH lo-beam shining, hi-beam shining, LH lo-beam dark as night.

I have made many rail-headed missed-diagnoses in the past, but not this time. :)

Thanks for the input.

Dang... :)

Well, as I understand it, the ZFE should sense that the circuit is having trouble and shut down that section of the line. Once the ignition is off, the ZFE should reset until it again senses that there is problems. I'm not an expert though. I guess the next step is to trace that back as far as you can? I can't remember off the top of my head if they will give you values, but do you have access to a GS911 or a Motoscan?
 
I asked the dealership's service manager if the ZFE had some sort of "reset" function, as you mention, which would allow it to see that the fault had been fixed, and she (yes, SHE!!) said she did not think so. I "assume" the tech who replaced the blown bulb would know if such a function were available and have implemented it when the new bulb would not fire. He did do a little troubleshooting, but evidently nothing was obvious to him in the short time allotted. I can understand that.

My Marine aircraft mechanic friend is leaning toward a wiring problem with the circuitry in the headlight nacelle. He has a GS-911 but does not think it will pinpoint a problem such as this close enough to be any help. And he lives about 90 minutes away.

I think I will just take the bike to them and see what they can find. I understand electrical concepts, but am not good at actually finding and fixing electrical problems. They can probably find the fault in an hour when I could try for two years and still never find it.

Oh well, we shall see.

I appreciate the input, as every little bit helps. :)
 
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