Brake light problem with servo ABS

[jrb1963]

A few days ago I noticed that the brakelight on my '03 model 1150GS has stopped working. No problem I thought - just replace the bulb/clean switch contacts etc. However, this wasn't the solution. I have since learnt that the brake light is switched via the ABS/servo assist unit. The handlebar and footbrake switches (switch is open contact when brakes are applied) run at low voltage and are just inputs to the ABS/servo unit.

Unfortunately the dealer's workshop team has concluded that the only way to resolve the problem is to replace the entire ABS/servo controller unit. The really bad news is that this unit costs about £1,000 (inc. VAT) plus as much as a day's labour to fit. To make matters worse the bike will have been off the road for the best part of a month by the time it returns to the dealers next year. Bike is just over two years old (by a few days), so original warranty has expired. May have to just take this one on the chin!

One factor in all of this may have been the connection of a Givi top-box with integral brake light. This was actually hardwired by the dealer (by mistake apparently as I am told this is not recommended (?)).

Has anyone else had similar problems or know of an alternative solution?

Can anyone suggest a temporary fix to get me back on the road e.g. a second switch on the front brake lever connected to the top box brake lights? Any legality issues?

Any advice much appreciated.

John

PS. Great website! Lot of helpful information/advice. Thanks to all.

 

[Tarka]

I`m very suprised to hear that the switches do not feed directly to the brakelights,as per the 1100,but thinking about why they do so,it is probably to provide a start command for the servo unit, and this will be why the servos do not function with the ignition off,and also why a low voltage is used.
If the braking system is functioning correctly,I would simply fit a hydraulically operated brakelight switch to either/both brakes.
These are basically banjo bolts with internal pressure switches, and two wires coming from the top.
Just replace your mastercylinder banjo bolts with them,pick up a switched 12v feed to one wire on each,and run the other wires to your brakelight bulb`s feed connection.
The switches are between £15 and £20 each,ask a decent bike spares place,or check out DEMON TWEEKS in Wrexham. They come in different threads,so make sure you get the right one.

Another alternative would be to do away with the daft servo arrangement,even if it meant losing the ABS system,and just pipe up your mastercylinders direct to the calipers,and wire up your brakelight switches conventionally.

Hope this helps,PM me if you need any more info.

 

[Fanum]

just over two years old (by a few days)

and

One factor in all of this may have been the connection of a Givi top-box with integral brake light. This was actually hardwired by the dealer (by mistake apparently as I am told this is not recommended (?)).

Then you shouldn't have to pay.

Speak to the dealer principle...politely, but firmly.....if he refuses to pay for it, write to him telling him you believe he is liable, and add that you will escalate.

Then call BWM, and follow up with a letter.

Keep copies of everything, and always be polite but firm.......the warranty is irrelevant if the thing has a design fault or if the dealer installed something incorrectly or against recommendations.....(if you can back that up with something when you go to the dealer then that's the way to go)


PS welcome to the nuthutch

 

[JohnnyBoxer]

and



Then you shouldn't have to pay.

Speak to the dealer principle...politely, but firmly.....if he refuses to pay for it, write to him telling him you believe he is liable, and add that you will escalate.

Then call BWM, and follow up with a letter.

Keep copies of everything, and always be polite but firm.......the warranty is irrelevant if the thing has a design fault or if the dealer installed something incorrectly or against recommendations.....(if you can back that up with something when you go to the dealer then that's the way to go)



PS welcome to the nuthutch

I agree entirely...................take it up with dealer and if no joy BMW GB

 

[Mouse]

Also, you say the bike is only just out of warranty. Did you report the fault to the delaer before the warranty expired? If so, you shoud be covered, I think.

 

[jrb1963]

Thanks everybody.

I am in the process of pursuing the warranty claim. Not pushing too hard just yet!! Still have the documentation to prove that the dealer was responsible for connecting the top-box incorrectly. I won't know what the initial verdict is until next year when the dealer will contact BMW warranty claims. Unfortunately the warranty expired a few days (~10) before I reported it to the dealer.

Interestingly, one of the guys at the dealers told me a story about BMW only honouring claims which are sorted, as opposed to reported, within the warranty period. Pretty cynical way of doing business IMO - but I don't think this is really the case. I vaguely recall an earlier thread on this subject.

Tarka,

Excellent suggestion on the hydraulic brake light switch. Just had a look at the bike and figure that with the combined brake system if I connect the switch to the rear brake line (e.g. where the flexible pipe connects to the frame) then it will operate with either front brake lever (F&R combined) or rear brake pedal (R only) applied. Just need to figure out what the dimensions of the banjo bolt/switch should be. I'm guessing a single length, M10 x 1.25mm bolt will do (about £15 from Demon Tweeks). I can then wire up the top-box to this permanently without fear of it trashing the ABS unit again. Would get me back on the road and shouldn't jeopardize ongoing warranty claim either.

Thanks again - will let you know the outcome.

J.

 

[jrb1963]

On second thoughts a hydraulic brake switch might not work very well on the rear brake line. The ABS may reduce the pressure too much to prevent the wheel locking up under hard braking.

Just trying to figure a way of getting one switch to do two jobs!

J.

 

[Mouse]

I guess with a hydraulic switch your brake light might flash if the ABS activates. But this shouldn't be a common occurance (is it? ) and maybe you could even view it as a safety feature! (A flashing light might alert someone behind you that you are stopping quickly ... maybe).

 

[Spout]

- just replace the bulb/clean switch contacts etc. However, this wasn't the solution. I have since learnt that the brake light is switched via the ABS/servo assist unit. The handlebar and footbrake switches (switch is open contact when brakes are applied) run at low voltage and are just inputs to the ABS/servo unit.

What the f*ck are BMW playing at?

Why can't they let the "brake light" be a "brake light"? - What's it really got to do with ABS/Servo wot nots? Surely they can have their own switch?

When I look at the 'spaghetti spillage' under my tank I realise I should have bought an airhead. I can't get my head round ever more complex solutions to non existant problems. Is it just me?

 

[Greg Masters]

Speak to the dealer principle...

Bill, standards are slipping!!

I think that this unfortunate matter illustrates how important it is not to use the brake light wiring as a supply for anything extra.

A £1,000 bill makes that a pretty expensive top-box!

Greg

 

[jrb1963]

Managed to get a hydraulic switch from my local Ducati dealer(M10x1.0mm, single banjo # GOOBL99231DV) for £14.99 incl.

However:

I just read a very detailed article on bleeding integrated brakes:

http://users.rcn.com/dehager/service/service_abs3.pdf

This is way beyond me.

Also discussed this modification with one of the senior technicians at the BMW workshop. While he was generally sympathetic with what I was trying to do, there was no way he could recommend/endorse this mod. In fairness, when pushed, he didn't say it would void the warranty as long as the connection was made to the top-box only and the wiring loom and connections were unaffected.

Lesson learnt - I have signed up to another year's BMW warranty (backdated to previous expiry date - but not covering this fault more's the pity) at £340. I was told there will be a substantial increase in extended warranty costs as of next year. A figure in excess of £600 was mentioned for 2005. Infer what you will from this!

Oh well... I hope no one else has the same problem. Only 20 days to wait

Time to start writing letters.

J.

 

[Tarka]

A hydraulic brake light switch will only function with pressure on it from its point of source,ie the one fitted to the rear master cylinder will only bring the brake light on if the rear pedal is pressed,likewise the front one on the front master cylinder will only function with the front lever operated.
Good luck withthe warranty claim,but if faced with mega bucks for a new unit,etc, I know what I`d be doing........

 

[jrb1963]

Tarka,

Not really sure what is connected where in this system - it's so complicated under the tank! Concluded the switch would have to be mounted on the front master cylinder. With the linked brakes I rarely use the pedal (Or the brakes at all it seems as I'm still on the original front pads at 28k!). The switch is in readiness should the warranty claim fail. I guess a solid state relay blew in the FTE unit, everything else is ok according to BMW's GT1 diagnostic thingy.

Next year's 1200GS is available without ABS/servo. The way to go for me. Just my personal taste, but I'm not really that keen on the servo/abs anymore. Too scared to service the brakes myself, not much feedback and the only times it's cut in has been when the back end has skipped over a cat's-eye when overtaking/filtering - find it quite unnerving to lose the front brake simultaneously. And when it snowed last time I fell off anyway

Cheers

J.

 

[Tarka]

As I suggested earlier,if all else fails,rip the lot out and re-pipe your brakes the proper way, with the front master cylinder controlling the front calipers,and the rear master cylinder for the rear caliper.

It`s like the good old days of the Kawasaki GPz1100 DFI fuel injection system packing up due to a Kaput £1000 control box....
the hot set up was to bin it all and fit a set of carbs!!

Luddites rule!!!

 

[jrb1963]

This matter has now been resolved with the dealer. I am very satisfied with the outcome.

Still not sure about the wisdom of having all of these braking functions integrated in one (expensive) unit. Time will tell.

Thanks to all who responded with advice and encouragement.