High beam not working :(

[UT R1150R]

I'm hoping for some advice from you fine folks...

2004 R1150R with 54,800 miles.

I've had a headlight modulator on it for about 8 years. Recently there was no modulation. Sometimes it would work, sometimes it wouldn't. Eventually it stopped altogether.

While trying to figure out the cause, I removed the headlight modulator (which sits between the headlight bulb and the plug). I plugged in the bulb and voila! the high beam worked.

Then, I decided to re-install the modulator. I'm pretty sure that during this process, one of the bulb's 3 tabs (that insert into the plug) touched the metal headlight bucket and possibly shorted out. The high beam again failed to function. I removed the modulator again and left it out.

I have tried several different bulbs and still no high beam. I also replaced the high beam relay and still no high beam.

I'm guessing...

1) There is a short somewhere in the wire that powers the high beam. The high beam power supply does not have a fuse (which makes no sense to me but that's what I've learned after quite a bit of searching the web).

2) The high beam switch on the handlebar is no longer working.

Any hot tips on how to verify 1 and / or 2 above?

Anything else I should check?

Thanks so much for any help with this problem!

[AZBMWRIDER]

Does the momentary position of the headlight switch turn the light on ????

[UT R1150R]

Does the momentary position of the headlight switch turn the light on ????

No, actuating the switch has no affect on it. It's always on low beam no matter the switch position.

[AZBMWRIDER]

Do you have a multimeter to check for continuity of the high beam filament in the light bulb ?

[UT R1150R]

Do you have a multimeter to check for continuity of the high beam filament in the light bulb ?

I do have a multimeter but I'm not sure which tab is the high beam filament. I'm sure I could figure it out though through some trial and error. Thanks for the idea!

I suppose if it has no continuity, then I should take apart the switch assembly and do the same thing there - trying to determine if there is current leaving and entering the switch. I will continue that process working backwards to the power source. Does that sound like the best way to tackle this?

[Frank1150r]

Have you checked the fuses ?

[UT R1150R]

Have you checked the fuses ?

It's interesting that you ask that. I had checked the fuses several times and found no problems. Someone on advrider told me that contrary to what the manual says, the high beam is fused.

After seeing his response, and since I couldn't sleep anyway, I went out to the garage to take a look at the fuses. None of them were blown so I decided to give up for the night.

Well, I changed my mind and decided to try to *add* another fuse. The fuses on my bike stop at slot #7. I popped one in slot 8 and *bling!* the high beam worked! I'm certain I had never removed a fuse from slot 8 but adding one worked so I must have.

I re-installed the headlight modulator and the light was blinking like normal. Then, just as I was about to put the lens assembly back in place, I tested it and the high beam did not function again. After some trial and error I decided that the modulator must be defective. I removed it and the high beam worked again.

Now, I love solving problems as much as anyone (especially the type that seemingly solve themselves) but I really wish I understood what's going on here. I suspect it's true that the modulator is bad - that may explain it's intermittent performance and apparent failure. What I don't understand is the fact that simply adding a fuse made the high beam function. Even my Clymer manual shows there is no fuse for the high beam, nor is a fuse indicated in the Clymer wiring diagram.

Anyway, it's great to have my headlight back to normal function.

Thanks for everyone's suggestions!

[sweatmark]

Have you checked the fuses ?

It's interesting that you ask that. I had checked the fuses several times and found no problems. Someone on advrider told me that contrary to what the manual says...
... Even my Clymer manual shows there is no fuse for the high beam, nor is a fuse indicated in the Clymer wiring diagram...

Incorrect.
R1150R 2003-2006 build date has fused low-and high beam. SLP confirms:

[UT R1150R]

^^ you are correct. I wish I had known about that much earlier.

For those following along... I think I know what happened. The modulator (only runs on high beam) would sometimes work and sometimes wouldn't. I concluded that it had eventually failed altogether. I checked my Clymer manual which said the high beam is NOT fused. The wiring diagram in the manual also showed no fuse for the high beam. I also found a lot of of info on advrider confirming no fuse. I posted the problem yesterday and a guy on advrider told me that BMW, Clymer and internet wisdom is wrong on this topic and that the high beam IS fused. I popped in a fuse and it worked. While trying to diagnose the problem, I must've removed the fuse at some point when trying to match my fuse block setup to what was shown in the manual.

Anyway, it's great to have a high beam again. I'll replace the modulator and cross my fingers that everything continues to function.

[gregor]

Historically ,and just a general point of interest, headlight bulbs were not fused. The received wisdom is that it was more likely you would have a nasty accident if a fuse blew in the dark than be spontaneously frazzled in a wiring loom fire.
Or something like that.