K11 Owners Group

John Clauss · Posted: Fri Jun 13, 2008 3:36 pm Post subject: Front brake light switch

Front brake light switch, issues. Took the bike to be inspected today and the front brake light switch is not activating the brake light.

Darn. So we go to find a new switch. Seems that the previous owner crashed the bike, and replaced the right side controls with those from a K1200.

So I got the switch, but the connecters didn't match up. No problem, cut off the old and solder the green to the green and the grey to the grey should be good to go.

Except its still not working. Now I have to investigate all of the wiring back to the tail light and see if I can find the problem. Any ideas?

I know that you helped me solve the foot brake lights switch issue really easily. Thanks in advance.
_________________
1997 K1100LT
1975 R75/6

It will bring you so close to nausea, it will make you sick! - Big Al

BMGraeme · Posted: Fri Jun 13, 2008 5:47 pm Post subject:

Take the tank off and trace the wire back to the small connector - check the connections with a multimeter to see if you have continuity. Might just be a dirty connection at that point anyway.
_________________
1980 CB900FA
1994 K1100RS
2008 R1200GSA

chopper_harris · Posted: Fri Jun 13, 2008 6:23 pm Post subject:

Have you bled the front brake recently ?

When I bought my K11LT for restoration, the PO had been bu**ering around, and the actuating arm on the front switch had been distorted.

If the m/cyl piston has moved beyond it's uaual range, this may have happened.

I managed to remove the two tiny socket head screws holding it in place (M3, IIRC), bend the actuator str8, and all was good.

Remove the plastic shield from the front of the m/cyl, and it should be apparent - you may find a trapped or corroded wire.
_________________
C1 200 (2001)
R100 RS (1990)
NSU Quickly N (1964)
Honda 400/4 F1 (1977)
MotoGuzzi 1000C (1978)
Suzuki TL 1000 R (1999)
Kawasaki KLV1000 (2005)
K12R Sport (2007) - Wifeys

John Clauss · Posted: Fri Jun 13, 2008 8:54 pm Post subject:

I doubt that chopper's solution is the problem as it did not work with the switch off the bike and in my hand, or on the bike. So its not a matter of movement.

I jumped the connector and still no brake light, so it must be in the harness. All looks good at the tail light and it does work with the back brake. Could it be a relay issue?
_________________
1997 K1100LT
1975 R75/6

It will bring you so close to nausea, it will make you sick! - Big Al

Flying Duck · Posted: Fri Jun 13, 2008 9:24 pm Post subject:

I don't think that thas a realy in the circuit - but it does go thorugh the bulb monitor unit= - somehow.
_________________
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

SugarHillCTD · Posted: Sat Jun 14, 2008 6:55 am Post subject:

John-

You mentioned that the bike has been repaired and the R.H. controls replaced. Any possibility that there were additional unseen things modified at that or other times?

-I see that the rear brake activates the light properly, but you checked all the fuses anyway? Do the gas and temp gauges work OK? (if there were other repairs by the P.O., the rear switch could have been run to a different circuit)

-Before you soldered in the new switch, did you try just "jumping" green to grey at the harness to see if it works?

-Did you manually work the new switch with your fingers after you soldered it in, but before you attached it to the brake lever? (replacement parts can be bad)

-If you manually close the OLD switch, do you get continuity at the pigtail?

I had a front brakelight switch go bad on me but it ended up being corrosion inside the two pin plug under the gas tank. It was on the harness side where the wire actually inserts into the pin, not where the pin inserts into the female socket. Drove me nuts.

Good luck- let us know if you find it or push the bike off a cliff in frustration.

John
_________________
John & Cathy

'92 K100RS4V Pearl White SOLD
'04 K1200GT
IBA Several-SS1k, BBG, 50CC NYC to S.F.

John Clauss · Posted: Sat Jun 14, 2008 7:34 am Post subject:

SugarHillCTD · Posted: Sat Jun 14, 2008 8:50 am Post subject:

The new switch might seem to work well, but does it really? An inexpensive multimeter is not difficult to use- otherwise you are just guessing about hidden open circuits.

Several members of this forum can give you a crash course in multimeter use. A small one can easily fit in with your tools for diagnosing problems while out on the road.
_________________
John & Cathy

'92 K100RS4V Pearl White SOLD
'04 K1200GT
IBA Several-SS1k, BBG, 50CC NYC to S.F.

Scott_Anderson · Posted: Sat Jun 14, 2008 11:20 am Post subject:

John, you didn't mention yet. When you turn on the ignition how does your red triangle brake like (in the instrument pod) funtion. Does it turn off with just the foot brake, or both, or does it stay on all the time?

That's my first indication when I have gotten my front brake switch wet as this dash light will turn off when I just touch the foot brake. The circuit "see's" my front brake as on, and of course the brake lights are also on.

If your front switch isn't working the dash light should be on all the time, unless something is f***ed up in the wiring.
_________________
Ride safe.

1995 K1100LT 0302044
2017 FLHTK Ultra Limited
Garmin StreetPilot 2820
Garmin Zumo 550
Garmin Zumo XT
"One who does not ask questions is ashamed to learn" Danish proverb
1997 K1100LT 0302488(R.I.P.)
1997 R1100RT ZC62149(sold)

John Clauss · Posted: Sat Jun 14, 2008 5:22 pm Post subject:

The dash light goes off with the foot brake only. Not the front brake.
_________________
1997 K1100LT
1975 R75/6

It will bring you so close to nausea, it will make you sick! - Big Al

Tim (Midland Section) · Posted: Sat Jun 14, 2008 5:55 pm Post subject:

mnb · Posted: Sun Jun 15, 2008 1:30 pm Post subject:

If only the rear brake is required to extinguish the dash light, then the front brake light switch is stuck or wired "on." This would be the problem.
_________________
M N B
1997 BMW K1100LT ABS Special Edition
2003 Husqvarna TE610e
2007 Harley Davidson Road King
2009 BMW F800GS
2011 Husqvarna TE310
2014 Ducati Multistrada Pikes Peak MNB Edition

John Clauss · Posted: Tue Jun 24, 2008 8:44 pm Post subject:

Ok, I dug into the wiring harness and discovered that the "hot" side is fine, not issues there. I also know that the new switch works fine as well. So in tracing the offening "ground" side wire it ends at the "Bulb monitoring device under the tank. So I jumped the wire from a known good point, to right at the bulb monitoring device, and guess what? Still no brake light. HAs anyone ever had one of these things go bad? Any idea how much one costs?

Tanks!
_________________
1997 K1100LT
1975 R75/6

It will bring you so close to nausea, it will make you sick! - Big Al

Flying Duck · Posted: Tue Jun 24, 2008 9:05 pm Post subject:

Yes, they can go bad.

$71 new

$25 used
_________________
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

John Clauss · Posted: Thu Jun 26, 2008 7:12 pm Post subject:

It was indeed the Bulb Monitoring Unit. Something for you all to keep in your memory banks for the future.
_________________
1997 K1100LT
1975 R75/6

It will bring you so close to nausea, it will make you sick! - Big Al