2005 R1200GS - rapid flashing Brake warning light = and no servo assist brakes

So this is an intermittent problem - after being parked, sometimes I have the rapid flashing brake warning light on the dash - and of course no power assist on the brakes. I'll ride for a while and it solves itself - or once I shut the bike off and restarted it and all was good.

I can still ride it, but obviously a lot more effort needed to actually stop the bike, so not good.

Any thoughts?

(And I did try our dreadful search engine and got nuttin relevant)

Bryan

No quick answer to the servo brakes. It could be as simple as low fluid in one of the wheel circuits, or it might be a failing servo assembly ($$$$.) You probably need a GS-911 to find out what fault codes are stored - then post them here and perhaps someone can make semi-educated guesses as to what the problem is.

Beemer01 said:

So this is an intermittent problem - after being parked, sometimes I have the rapid flashing brake warning light on the dash - and of course no power assist on the brakes.

Click to expand...

Unfortunately that is a very generic code meaning that you have only residual braking in one or both circuits. Which you already knew. You'll need a code reader to know more.

Had a similar problem on my '05 a couple years back. Problem turned out to be the micro brake switch on the front brake lever. Sometimes it would stick in the applied position (meaning the brake was activated and the rear brake light on). When that happened I got the flashing light and no servo brakes because the system could not finish it's diagnostics. Same thing can happen with the rear brake pedal, often because of dirt or a small stone lodged in the switch.
Next time you get that symptom check and see if your rear brake light is on. If so the switch could be the source of your problem.

Texpaul nailed it

So I got up Saturday and tackled the problem.

What I found was that the microswitch in the handlebar brake lever had shifted a tiny bit, causing the flashing warning on my dashboard. The Haynes manual is actually pretty useless in this case - what we all should note is that the microswitch position is adjustable, there is a very small Allen bolt on the underside of the handlebar brake assembly that holds the switch in position.

The inboard side of this small switch pivots on a fixed pin, the outboard side has a tiny machined metal piece that protects the plastic microswitch and provides a durable pressure 'plate' for the allen bolt to snug up to. If this switch is even 1/64th" out of position, the result is the brake lights continuously illuminated, the rapidly flashing dash light and I discovered, the ABS pump running nonstop. Note, you can test all of the above by gently removing the microswitch and opening and closing the metal strip across the contacts.

Thanks for the tip Texpaul!

Good news on the fix...yeah that allen adjustment is finicky for sure. We have had one give us fits on a K bike. The 1.5 mm allen is easy to strip as it seems it got a drop of threadlock at the factory on some.
The handguards were redesigned after 05 as well, they would rotate down and contact lever which would cause same operational issues. They mailed out warning labels to be placed inside the handguards, complete with a schematic of proper angle

Thank you! This thread saved my butt today!

So I got on my new-to-me 2005 R1200GS today to go meet some people for a breakfast ride and notice the brake warning light didn't go out when I took off and it took a lot of effort to stop. I was hoping maybe I just needed to turn the bike off and let it go through the diagnostic again. I'm running late so I figured I'd limp along with the reserve brakes until I got to the meeting place and do it there. Nope, didn't help. I got there late and missed the ride so I went to the McDonalds next door to get breakfast and Google the problem. This thread was the first thing to come up on an Internet-wide Google search. Reading this tip about the front brake switch and the hand guard reminded me I had taken the right bar weight off the night before and put it back on. Maybe my hand guard is rotated down too far? So I go out and move the hand guard up and problem is solved! What a relief! I was fearing the worst and thought I'd be shelling out hundreds of dollars for a new servo. I was able to go riding the rest of the day with great brakes thanks to everyone posting on this thread with their suggestions for the original post.

Fine job

Yeah, that happens more than you know. Glad it worked out.