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Mungrel
Joined: 25 Nov 2021 Posts: 5 Location: Manchester England
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Posted: Fri Oct 07, 2022 2:27 pm Post subject: K1100LT Bulb Monitor Unit?/ what is it and where is it? |
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Greetings all from our now usual default-setting wet North of England. I have a 1992 K1100LT which has undergone some radical surgery over the summer.
I have removed all the old ABS system, the wiring, the sensors, the ECU, dead spiders and anything else I could find. I had a pal make me up some custom braided steel hoses and had all my calipers reconditioned and repainted. It stops on a small denomination coin now.
The rev counter went south in the one day we had really hot weather, so I sourced a replacement instrument cluster from a breaker's yard, but it's from a '96 special edition and looks prettier.
Anyhow..... The red triangle lamp is constantly lit, with flashing on and off occasionally just for a laugh. Is this the bulm monitor unit working ? I noticed that the brake light wasn't working because I'd pulled a wire off when messing about removing yet another oddly placed wire that I believe had powered a rear fog lamp at some time in the last 30 years.
I have soldered a new connector on and all is good with the light again but the red triangle still illuminates. Should I just remove the bulb and be done with it?
Thanks for any help |
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Flying Duck PsyKotic Waterfowl
Joined: 27 Jan 2005 Posts: 10087 Location: Bumf***, WA
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Posted: Fri Oct 07, 2022 8:13 pm Post subject: |
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If the "triangle light" is flashing then that's from the ABS warning relay, not the BMU.
Did you remove both of the BLUE ABS relays when you got rid of the ABS?
_________________ 93 LT (x2)
94 RS
86-97 K75F(K75/100/1100 Frankenbrick)
86 K75C w/paralever, hi perf cams,TURBO!
91 & 92 K75Ss
91 K1
86 custom K100
14 WR250R
IBA #17739 (SS1K, BBG, 50CC)
Buy parts HERE |
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Flying Duck PsyKotic Waterfowl
Joined: 27 Jan 2005 Posts: 10087 Location: Bumf***, WA
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Posted: Fri Oct 07, 2022 8:18 pm Post subject: |
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If it goes on an off randomly then it could be a bad brake or tail light. When bulbs get old they may still illuminate but not be good enough to make the BMU happy.
Check the contacts of those bulbs and/or replace them with new bulbs. _________________ 93 LT (x2)
94 RS
86-97 K75F(K75/100/1100 Frankenbrick)
86 K75C w/paralever, hi perf cams,TURBO!
91 & 92 K75Ss
91 K1
86 custom K100
14 WR250R
IBA #17739 (SS1K, BBG, 50CC)
Buy parts HERE |
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Mungrel
Joined: 25 Nov 2021 Posts: 5 Location: Manchester England
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Posted: Sat Oct 08, 2022 11:48 am Post subject: |
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Flying Duck wrote: | If it goes on an off randomly then it could be a bad brake or tail light. When bulbs get old they may still illuminate but not be good enough to make the BMU happy.
Check the contacts of those bulbs and/or replace them with new bulbs. |
1. Yes, I've removed both the blue relays. That's what has thrown me: it sometimes flashes on and off, sometimes just steady red.
2. When I've changed the bulbs, will the triangle red light go out on it's own accord, or do I have to ctrl-alt-del or something?
Many thanks for your help
Andy |
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Flying Duck PsyKotic Waterfowl
Joined: 27 Jan 2005 Posts: 10087 Location: Bumf***, WA
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Posted: Sat Oct 08, 2022 3:51 pm Post subject: |
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Turning the key off is ctrl-alt-delete. (Except for the clock and flasher relay.)
Does the tail light work?
The BMU also monitors the brake switches.
Does the brake light come on when you hit either brake?
You can also check/clean the rear lighting connector under the tail light lens.
If you want to disable the BMU light you can pull the instrument cluster bulb or use a needle/pin to pop the terminal of the white/blue wire out the BMU connector in the relay box.
_________________ 93 LT (x2)
94 RS
86-97 K75F(K75/100/1100 Frankenbrick)
86 K75C w/paralever, hi perf cams,TURBO!
91 & 92 K75Ss
91 K1
86 custom K100
14 WR250R
IBA #17739 (SS1K, BBG, 50CC)
Buy parts HERE |
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Mungrel
Joined: 25 Nov 2021 Posts: 5 Location: Manchester England
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Posted: Mon Oct 10, 2022 11:22 am Post subject: |
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So I did everything as suggested: New bulbs, cleaned every connectionin could find. Fantastic! The red light now goes out when I apply both brakes to check.
Then I'm coming home on the motorway today and indicate to overtake a truck and the red light now flashes on in time with my right side indicators ( our offside).
Done the same with the bulbs etc...no change. I guess htis bike has a sense of humour
Thanks for the help and advice...I think the electrical Gremlin likes taking the mickey out of me
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Grunter Flying Brick Rider
Joined: 30 Sep 2015 Posts: 369 Location: North East England
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Posted: Mon Oct 10, 2022 1:55 pm Post subject: |
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The bulb monitoring unit is one of the most useful 'add ons' that BMW ever thought about and fitted to the K series bikes. Likewise the signal cancelling system so they are not left on for too long.
I cannot understand when such a possible life-saver as the BMU was not continued on the later R series bikes. Far more useful than heated seats - that is one place on my anatomy I never seem to get cold! _________________ 1997 K1100LT
1994 R1100RS |
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Flying Duck PsyKotic Waterfowl
Joined: 27 Jan 2005 Posts: 10087 Location: Bumf***, WA
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Posted: Mon Oct 10, 2022 6:00 pm Post subject: |
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Grunter wrote: | The bulb monitoring unit is one of the most useful 'add ons' that BMW ever thought about and fitted to the K series bikes. Likewise the signal cancelling system so they are not left on for too long.
I cannot understand when such a possible life-saver as the BMU was not continued on the later R series bikes. Far more useful than heated seats - that is one place on my anatomy I never seem to get cold! |
I've never seen the need for heated seats either. (Even in a car.) _________________ 93 LT (x2)
94 RS
86-97 K75F(K75/100/1100 Frankenbrick)
86 K75C w/paralever, hi perf cams,TURBO!
91 & 92 K75Ss
91 K1
86 custom K100
14 WR250R
IBA #17739 (SS1K, BBG, 50CC)
Buy parts HERE |
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Flying Duck PsyKotic Waterfowl
Joined: 27 Jan 2005 Posts: 10087 Location: Bumf***, WA
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Posted: Mon Oct 10, 2022 6:09 pm Post subject: |
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Mungrel wrote: |
Then I'm coming home on the motorway today and indicate to overtake a truck and the red light now flashes on in time with my right side indicators ( our offside). |
If the BMU is going off with a turn signal then it could be that the inside of the starter motor is dirty. Part of the K bike electrical grounding goes through the starter and when that gets dirty from wear inside it can cause all sorts of wonky electrical gremlins. If your turn signals start acting more wonky then that is the usual suspect.
Some people dismantle, clean and rebuild the starter motor when that happens but I think it's easier and cheaper just to swap in a low mile starter motor from Ebay or wherever. The same starter motor was used on K1200s too so there's plenty of them floating around.
Or they may be some shorting going on in the clump of wires from the relay box to the tail. _________________ 93 LT (x2)
94 RS
86-97 K75F(K75/100/1100 Frankenbrick)
86 K75C w/paralever, hi perf cams,TURBO!
91 & 92 K75Ss
91 K1
86 custom K100
14 WR250R
IBA #17739 (SS1K, BBG, 50CC)
Buy parts HERE |
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