HELLO ALL......i WANT TO SAY THIS FORUM IS FULL OF MANY KNOWLEDGEABLE PEOPLE..AND THANK YOU FOR THAT.. OK WELL I HAVE BOUGHT A 1985 K100 AND AM SPENDING SOME TIME CLEANING IT UP AND GETTING TO KNOW IT...HOWEVER...I DONT HAVE AN OWNERS MANUAL AND WANT TO KNOW IF SOMEONE CAN CLUE ME IN ON A LIGHT ON THE GAGE CLUSTER..IT IS THE RED LIGHT WITH A TRIANGLE ON IT JUST ABOVE THE NEUTRAL LIGHT....IT IS ON ALL THE T IT IS FOR...ANY HELP? THANKS ALLIME AND FOR THE LIFE OF ME I CANT FIGURE WHAT

It's the check light for the brake light. When you operate both the front and rear brakes it goes out if both brake light switches and the brake light bulb are OK. If any one of them is faulty it stays on. Not sure if it works for the tail light as well, never tried taking out the tail light bulb to check.

Yep, it checks the tail light bulb as well.

If you do all your checks (switches, bulbs etc) and it still remains lit, sometimes you may need to replace one or both of the rear bulbs. It seems to "sense" when a bulb is coming to the end of its life, which is enough to illuminate the warning light.

Hi Dabosswd

Have a look and a read of the Download section. There is a pdf of the manual available. Otherwise check ebay for paper manuals. They come up all the time...

regards

mal

I had this trouble as well. Found it was just a faulty switch on rear brake . Removed and cleaned tested with meter and was all good.

Same problem, was advised here to check the front brake switch up near the
front master cylinder on my old crate, the piston wasn't springing back far enough. A good cleanout and a touch of moly grease and it was fine.
Cheers RT

A similar problem has arisen with my dash brake warning lamp. The light is on full time despite all indicator, headlight, parking light, and tail light/stoplights functioning. Their sockets, wiring and connectors are tight and have been cleaned up with Deoxit. The front and rear brake light switches, their leads and connectors have also been Deoxit-ised, and are clean and working. The only trick I haven't tried yet is to clean the connector at the bulb monitoring relay, which I have yet to rip into. The globes (bulbs) seem to be in good nick with no burn marks or fragile filaments evident. An option I'm considering is to replace all of them just because I don't know their age or whether they've stayed out late at night when I wasn't looking. Kids these days!

Having a squiz at the wiring schematic in the Haynes manual shows only the globe (which obviously works) and the single white/blue wire leading to it in the dash itself as possibilities of something wrong internally in the dash. I have just recently removed the instrument cluster to repair the odometre. There doesn't seem to be a pinched wire leading up to the dash itself and, of course, the twin connectors at the back of the dash were treated with Deoxit before replacement. The problem appeared at some stage after refitting the dash, so I'm wondering if looking inside there again for something is worth the effort, but am tending towards excluding that possibility since there is only the globe and a single wire in there in this function and they obviously work or I wouldn't have the issue. A nice piece of black 'lekky' tape covers the evil red glowing eyeball now.

Hints and suggestions not already covered by my extensive attempts at a solution are welcomed.

PS, I've managed to write Deoxit, three, err, four times.

Replace the bulb monitoring unit with another known good one. I reckon that is where I would be going next.
Maybe just take the relay out and confirm it is not likely to be a pinched wire somewhere.
If we get together later in the week for a ride we could swap it around then.

"PS, I've managed to write Deoxit, three, err, four times."

Yeah, but still can't spell it correctly ya nong!

D e o x I T DeoxIT DeoxIT DeoxIT

Ok, there is a procedure to eliminate the BMU if you wish, that I found on the Interweb a while back...


Unbolt the BMU and remove it from its relay socket.

Using short segments of wire and blade terminals:

1. Jump the front brake switch wire (Grey/Red) and the rear brake switch wire (Grey/Green) to the rear brake light (Grey/Yellow.)
   
2. Jump the tail light power (Green/Black) to the tail light wire (Grey/Black.)
   

Note that those are the wire colours for a 94 K1100RS. It's advisable to check that your wiring colours are the same before doing this!



CAUTION: This removes the functionality of the BMU which also tests your front and rear brake switches. Be sure to include those in your pre-ride checks once you've removed the BMU.



You are all adults out there, so you are on your own if you do this modification.



Thus endeth the lesson.

What would I do without my pedantic friends? That's rhetorical.

Dee-oxe-et is yer fren.

There's heaps of those 61 31 1 459 003 BMU relays on eBay. Some for as low as a pink note, and all in Amorica.

Motobins have it for under $60.

I like its function, but I'll do the re-wire trick if it turns out to be playing up on me. I usually do the tyre tread, obvious loose bit hanging off, burnt-out globe, nothing dragging on the tarmac, walk-round before a ride anyway.

twb you should see that light up front dim slightly when applieing the brake up front and down the back ...if not you know its the switch/s

in any case ...i had mine come on by itself when descendning nebo one ti me .

i found that the globe needed replacing ....worked ok though ....whilst replacing that brake globe i noticed that the contacts connecting into the globe had worn some of the solder at the centre electrode ....its been working fine eversince the change over and some application of the deoxIT to the contacts .......more specifically the contacts on the feed terminals to the rear light assembly (spades) as they were showing signs of corrosion internally.

just some thoughts that may help mate....cheers

Yep, the neutral light and the warning light both dim ever so slightly when the front or rear brakes are applied. I've now replaced all of the indicator and tail/stop light globes with new, and cleaned up their spade connections and sockets too. I whizzed the BMU out from under the back of the petrol tank, took the relay apart and found no visible evidence of a popped diode or heat marks on the solder - I realise this is not definitive. I also cleaned and Deoxit-ised the multi-pin connection to the unit. The evil red eye stays lit. The tape works beaut, so much so that I didn't worry about it on my ride this fine, sunny arvee! I'll keep looking, though.

In the BMU it`s reed switches which monitors the current flow.
Those ones depends on a certain amount of power must pass to close the contacts,
.....the bulbs must have the correct wattage, 10W for tail and 21W for brake.

Haven`t tested this myself, but I`ve read that putting in 5W in tail is enough
difference to make the BMU malfunction.

Inge K.

I used a 10W in the tail light position and took out a 10W, and used 21W for all of the others. Tomorrow I'll have a squiz at the instruments again, though I cannot see any interference with any of the wires going into the back.

That black tape is holding up well.

"Haven`t tested this myself, but I`ve read that putting in 5W in tail is enough
difference to make the BMU malfunction."

I have a 5 watt bulb in the tail light all the time and the B.M.U. works fine. I noticed that the plastic surrounding the bulb holder was scorched, presumably from 10 watt bulb, so I substituted it with a 5 watt. It works fine and is bright enough.

well guys.....i think i figured out my problems......battery replaced again from store....other was a dud.....now take the key out when i park it...did not know it continuously checked lights even in off position.....now to the next fix....when i pull the front brake then step on the back the back does not light up every time...definetely most likely <grin> a dirty connection.....getting there slowly but surely...thanks again for all the great advice

The 'early' BMU relays used three reed relays inside the box but this was apparently changed in later models. Mine is the later design. I am not the original owner of this 'late-'86 K100 so I have no history to go on. I suspect it was changed by the PO and perhaps the factory changed the design when ABS was introduced in '88 or so. The 'early' relays have 51 13 1 459 003 stamped on them and later versions have part number of 61 13 1 459 003, if this helps anyone in identifying theirs. As a parts purveyor for a lot of years I find it interesting that BMW used a 51 prefix to the part number, though it's electrical, 51 usually indicating the body equipment section of, and 61 tending to be in the electrical section, of ETK.

My search for a cause and definitive fix continues.

To confirm Blakey's 'fix' which he located somewhere on the intertron... The simple bypass method is to remove the plug-in unit, and on the multi-pin connector inside the relay box under the back of the petrol tank, jump the grey-red and the grey-green to the grey-yellow. Also jump the green-black to the grey-black. That done the 'roo in you will be pleased.

The other problem that affects machines of our vintage is cold solder joints in relay boxes which can be hard to spot. If the solder joints are reflowed with an instrument iron and electronics solder then that often fixes the problem. These are often vibration related failures as much as suspect soldering.
Regards,
K-BIKE

I had a day off today and while it rained a bit I played round with the bike. I had some good fun. I love pottering in the garage on a warm, Winters' day. So at this stage I have physically touched and cleaned (Deoxit, Deoxit, Deoxit) every connection, socket, switch, lead and changed all of the bulbs in the BMU's little universe. Short of swapping a known good unit into its place to be certain I suspect it's the unit itself. I have a Sherlock Holmes-sized magnifying glass and scoured the solder for breaks from vibration and/or heat and none can be seen on the outside of the river of solder in that little black box. You know they run on FM! F*cking Magic. Apparently Holmes had a cocaine addiction. I'll happily reward myself for my efforts with a snifter of decent single malt instead.

K Freak, if you've got a good spare and you, me and Charlie (and anyone else who wants to ride along) ride that twisty, curvy bit of northern New South Wales road this weekend I'll check it against mine, if that's all right. Ta.

I have got one here but I am not sure it works so I will put it in tomorrow arvo and find out. let you know in 24 hrs or so.
It's a bit dark at the moment and all the polar bears are out playing in the snow. Been a shite of a day today about 8deg.

i can reflow all the solder for you ....(has one of them gas solder thingys) ...for when the mains power isnt close ...or can take it into the workshop if need be.

You know I have a really big magnifying glass cause I'm going blind ( the priest was right) and I swear when I have a look at my brand new
Deoxit sprayer, on the side it says "distributed in Australia by TWB industries, 2561 Sucked In Drive N.V. Am I right, am I right. It does work tho.
Cheers men have a good ride RT

Well TWB you put the mocca on me and today mmy BMU chucked it in. Actually it is a bad joint between the BMU and the instruments so I will get into it Friday.
I will bring the spare regardless (I think it is OK).
So now for the ride where and when. I propose meet at Drake about Noon and have lunch there and back up the hill to Tenterfield that way I can ride it twice and you guys will plenty of time to get home before the furry grasshoppers come out to play.

Oh, too bad about that. Bad ju-ju for sure. The lekky tape works a charm over the evil red eye.

Drake sounds good to me, but which day is best, the Saterdee or the Sundee? I'm open to both, and except for a 16 degree high instead of our coastal seasonal low 20s forecast, the weather liars haven't spoilt either day as yet. It looks to be sunny up in them thar hills at the weekend. Now that the sun begins its rapid drop at about 5.07PM these days we have heaps of daylight.

I'll see when Charlie's back from the far North.

Saturday or Sunday is OK so I guess its whenever Charlie is willing and able

i guess im ok either day .......possibly saturday ..... will be back early friday night ...and sunday i need to catch with the bed and filter and oil changes

maybe a 8.30 start twb ?

now choices ....m1 to lismore, casino or beudesert to kyogle,casino over the mt lindsay?

in your hands

its about 80ks to my area (maybe maccas at calamvale pub on corner of compton and beaudesert road http://www.bing.com/maps/?FORM=Z9FD#JndoZXJlMT1Db21wdG9uK1JkJTJjK0NhbGFtdmFsZSUyYytRTEQrNDExNiZiYj0tMjcuNjA3MzQ5NDY0NDgyNCU3ZTE1My4wNTc1Mzc4ODgwNTElN2UtMjcuNjE1MDc0ODk5NjIzOCU3ZTE1My4wNDU5MTM4NDIxNTU=) from nerangbar and probably the same to yatla if doing the m1

I'm go, Charlie. Gimme a bell or an email and we'll make a plan. The address you've given me for Calamvale is less than an hour from here. I could do that by 8.30am, no worries. Coastal showers tomorree, cooler inland, but mostly fine!

Sounds fine to me so Drake at Noon.
I have a spare BMU that works and will bring it with me but the story is strange. I went to check it and realized that mine wasn't working either so I chased things around and found was between the instruments and BMU. Put the other one in and it worked ? but I still didn't have a good one for test on TWB so I get the one out of the K1100 and it works in mine and the K1100 so I put my original in K1100 and it works so put it back and no go in K100. Stuffed if I know.

nice stuff ......wtf? kfreak whats the story ? ima thinking to pack my multimeter and soldering iron ...it seems them bulb monitoring circuits are kinda tricky huh ?

good news twb ...ill be ready ...yeah maybe the mirror pod might be held on by a lacky band but its all good ...giggles
ill give ya a call, just made it home.

It's only nine but I'm about to drop from a busy Friday so I'll be up before sparrow fart and ready to go. Charlie, I reckon I can be down your way (the Calamvale map) by eight/eightfifteen-ish. Too early?

Gimme a hoi in a coupla minutes to firm up otherwise I'll see you there then. Cheers.

its all good see you there

Hey, Blakey! If you wanna get up early and have a good day ride, probably home by dark, gather up with me per Charlie's Bing map above and meet up (or ride down with me) to Calamvale bright and early tomorrow morning. Cheers!

We took this fine thread and ran away with it, stole off with it, far, far away! I remember something about red warning lights on the dash. Well, at least it's about motorbikes... It's 6.55am, sunrise is clear as a bell, East coast Down Under time. On the road soon. Cheers.

Sorry TWB, family matters made me miss this ride.

Hopefully another time.

aww ...poor blakey ....we understand mate ....we have more plans to come ...just hope its all getting easier day by day ...chin up i got some pics to post


good news on the design of the bmu though .....it is apparent that there is about 3 circuits for the monitoring .
looks as though there is 3 bands of resistance/ shunt ( i guess maybe its resistance wire)

a quad nand gate ic ...4011 a uln something possibly a comparitor/driver device, a few diodes and resistors .

unfortunatly resoldering the external terminations wasnt able to recover the operations on twbs unit .

hopefully he will find a replacement ....and give the old one to me for further investigation ....(im thinking at this time that the 4011 ic ( cmos device and suseptible to static discharge ) will be the problem ...their cheep and plentifull ...without real world rectification as of yet ...im thinking that durring the exchange of globes and disconnection of the wiring harnesses maybe a spike has damaged the 4011 .

time will tell but all information input is helpfull

Didn't I have a fun adventure! After a fine day of riding, well after dark, the temps dropping, and waving 'see ya' to Charlie as we motored along the Ipswich Motorway towards our respective homes I missed my exit. I was looking for a hint of something suggesting 'North' or 'Sunshine Coast' but, alas, they don't think that far ahead. I ended up taking the M5 into the heart of Brisbane past the base of Mt Coo-tha, then past the Castlemaine XXXX factory, whilst a thugby game or something else was on at Suncorp Stadium. Cops, traffic and pedestrians everywhere. No worries, thought I, I'll just that exit for the new Clem 7 tunnel under the city and the Brisbane River which I'd just spotted out of the corner of my eye. The only problem was/is that the powers that be don't often tell you which direction you're going while driving Down under. You sorta have to know the name of the next town or you're stuffed. I looked for any sign of the northern suburbs and ended up going south on the M1 back towards the Gold Coast. An extra hour later I made it home, cold and tired, but happy about a excellent day of riding through some of northern New South Wales most rural and best motorbike roads. Thanks to Charlie and K Freak for the help with diagnosing the BMU. It is kaput.

oh ??? bugga ....i knew there was something wrong .....just near where i peeled off ...was the turnoff twb ....that sign that said logan--sunshine coast ...the little left lane exit is the gateway hookup ...my fault for not pulling you up and directing the turnoff

if you has followed the "icb" you would have joined up again at kingsford smith and the gateway out the other side ...ascot area (which is my normal route north )

"that sign that said logan--sunshine coast" in my mind reads Logan - Gold Coast, and that's why I didn't take it...but anyway, I come up short on the motorways since the two lane roads are my real preference. Also, I don't know Brissy's west very well. It was a good ride into the city, albeit a bit longer than I wanted or needed after three hours in the dark from Stanthorpe. I'm glad for having the decent riding gear in my pannier before it got cold. And how many cars did we overtake on the way back? ALL of them ! LOL

I've managed to buy a used, guaranteed BMU on eBay from somewhere in Los Angeles for less than an Aussie pink note ($20) plus postage. They sell new for over a hunnerd here in the land of the extra mark-up. He has two more left if someone else wants a spare or needs a replacement. I've done business with him in the past with no worries.

http://cgi.ebay.com.au/ws/eBayISAPI.dll?ViewItem&item=370507164157