brake light stuck on

darksider · Dec 16, 2016

since replacing the rear brake pedal the brake light has been stuck on.
when I turn the ignition on the tail light comes on then almost immediately the brake light.
there doesn't seem to be a switch of any kind for the back brake so does anyone know how it works or how to fix it ?

thanks

kuksul08 · Dec 16, 2016

There is a little switch down there. Looks kinda like a pin.

darksider · Dec 16, 2016

kuksul08 said:
There is a little switch down there. Looks kinda like a pin.

thanks kuksul, found the little blighter, the pin moves but the light stays on so have disconnected it for now. will get it sorted under warranty when it goes in for the 9k service next month (year).

edgary · Mar 6, 2017

Let me follow up on this since I just had the exact same thing happen to me.

I replaced the rear brake lever a couple of days ago. Yesterday I took the bike out for a spin and during the pre-ride check, I noticed that the light was stuck on. Did you get yours fixed? More information would be very helpful before I tear everything open to try and diagnose the problem. More info on exactly what I did:

Since I didn't have enough room to remove the screw that hold the pin that activates the rear brakes, I removed the exhaust first. Then slowly (read, with little room) unscrewed the back screw, left the pin in the brakes cylinder and proceeded to remove the screw that holds the lever itself.

As I was putting it back together, I noticed that the pin easily comes out, which allows a different removal procedure where you leave the exhaust in its place and just remove the screw holding the lever, and take the pin out, along with the lever, off the bike and replace everything on the new lever off the bike.

Alas, I placed the pin back in its place and screwed the lever to the bike first. Then I used zip ties to hold the return spring high enough to clear the cylinder where it normally sits while I put the back screw back in place. Cut the zip tie and the spring lays where it should. I tightened everything and turned the bike on.

The lever works as expected, engaging and disengaging the rear brake normally, but the light is constantly on. It doesn't change with neither the rear nor front brake lever usage. I have verified that the aforementioned pin goes out of the cylinder as much as it used to before replacement yet the light is stuck on.

It seems like yours was the exact same scenario: the brake (lever, pin, cylinder, pads) was working normally but the light was not. Did you get any information from the Ducati techs?

zibbit u2 · Mar 6, 2017

When your replacing your lever, first thing you have to adjust is the stroke of the Rear Master Cylinder via the turnbuckle which extends from the Master Cylinder (I'm pointing at the turnbuckle). Note that you have to maintain that the Master cylinder arm can fully extend when the lever is in its resting state (you're not touching the lever), otherwise your rear brake won't be able to draw new fluid into the system to account for brake pad wear.

Now you have adjust the Rear Brake light Microswitch via the bolt & nut I'm pointing to. How this is done is, when the rear brake lever is in its resting state, the bolt should just touch the rearset, thus applying inwards pressure to the little black pin that extends from the Microswitch. You can adjust the height of the brake pedal via this bolt as well. If you want the pedal to be lower, then you screw the bolt in so it protrudes farther out the lever. If you made a height adjustment, check the turnbuckle on the master cylinder to make sure it still extends to full stroke.

If the light continues to stay on, then you've probably got a problem with the rear microswitch being faulty and in need of replacement.

edgary · Mar 7, 2017

Thanks for the prompt and detailed reply.

I hadn't thought of messing around with those adjustments, given that I didn't change their settings when putting the new lever in but it certainly doesn't hurt to make some changes and report back.

Hopefully that fixes it...

edgary · Mar 9, 2017

I've got an update for you curious peeps.

I went ahead and did the adjustments suggested above with no luck. I looked around the rear brake pump to try and find something obviously out of place, to no avail.

I then decided to take the rear brake lever out again, mostly to see if the light was still ON with the pin (turnbuckle?) completely out of the pump. Sure enough, the light was still ON without it.

I noticed that there was very little grease and it was pretty dark so I put a dab of grease on the pin and reassembled the lever as I was thinking of other places where I should look; it seemed to me like it would be an electrical fault.

Once reassembled, I checked the travel of the lever and turned the key to the ON position. Lo and behold, the light was working normally again. The problem was that I had failed to put grease on it the first time I replaced it.

Imthedecidah · Aug 14, 2020

Let me join in here.... I have brake light mode stuck ON -- I have done all that is recommended above and still cannot get my brake light to turn off bright mode to riding mode. Even with everything taken apart the brake mode stay on so I am guessing its the sensor. I hate to disable/disconnect the sensor but need to ride.

-- Can someone walk me through detaching the sensor wire I don’t want to break one of the connectors and its super tight in that space w/o removing rear sets -- which I haven't done bc I do not have a stand and it looks like center stand is held on by some of the rears bolts.

Last thought -- could there be anything relating to brake fluid pressure that would make the sensor stay on even when all is taken off and the sensor port/hole is visible to naked eye?

I am at a loss after 2 attempts of disassembling and re-assembling.

Any way to check something w/a multi-meter?

Thanks for any help!

...busted rear brake lever playing in the dirt

gatdammit · Aug 17, 2020

Most likely the switch actuator near the plunger assembly on the end of rear brake lever. This is not hard to take down and reassemble. The plunger can get stuck and gunked up. Clean up the area where the plunger/actuator meet and lube it.

Possibly a short. The stock rear lights are traditional bulbs, which could cause a short. Are all the bulbs working?

Imthedecidah · Aug 17, 2020

its the plunger on the stop switch for sure -- I can de-actuate the brake light (make it go dim to ride mode) by inserting a hex key inside -- it looks as though the plunger originally had a male part that would have been plunged inward by the round head of the set bolt on the brake lever. I need to figure out how to replace this switch and the cord w/o removing the rearset if at all possible

edgary · Aug 17, 2020

It's easy enough to do, if a little tight. Simply remove screw #11 in the diagram below; it seems like part #19 is broken for you, replace with a new one. Don't forget about part #15, nor to grease the pin in #19 before reassembling.

RennyRacer · Jun 23, 2021

zibbit u2 said:
When your replacing your lever, first thing you have to adjust is the stroke of the Rear Master Cylinder via the turnbuckle which extends from the Master Cylinder (I'm pointing at the turnbuckle). Note that you have to maintain that the Master cylinder arm can fully extend when the lever is in its resting state (you're not touching the lever), otherwise your rear brake won't be able to draw new fluid into the system to account for brake pad wear.

Now you have adjust the Rear Brake light Microswitch via the bolt & nut I'm pointing to. How this is done is, when the rear brake lever is in its resting state, the bolt should just touch the rearset, thus applying inwards pressure to the little black pin that extends from the Microswitch. You can adjust the height of the brake pedal via this bolt as well. If you want the pedal to be lower, then you screw the bolt in so it protrudes farther out the lever. If you made a height adjustment, check the turnbuckle on the master cylinder to make sure it still extends to full stroke.

If the light continues to stay on, then you've probably got a problem with the rear microswitch being faulty and in need of replacement.

RennyRacer · Jun 23, 2021

zibbit u2 said:
When your replacing your lever, first thing you have to adjust is the stroke of the Rear Master Cylinder via the turnbuckle which extends from the Master Cylinder (I'm pointing at the turnbuckle). Note that you have to maintain that the Master cylinder arm can fully extend when the lever is in its resting state (you're not touching the lever), otherwise your rear brake won't be able to draw new fluid into the system to account for brake pad wear.

Now you have adjust the Rear Brake light Microswitch via the bolt & nut I'm pointing to. How this is done is, when the rear brake lever is in its resting state, the bolt should just touch the rearset, thus applying inwards pressure to the little black pin that extends from the Microswitch. You can adjust the height of the brake pedal via this bolt as well. If you want the pedal to be lower, then you screw the bolt in so it protrudes farther out the lever. If you made a height adjustment, check the turnbuckle on the master cylinder to make sure it still extends to full stroke.

If the light continues to stay on, then you've probably got a problem with the rear microswitch being faulty and in need of replacement.

Just stumbled on this malady on my 939. Oil change, tp check, a little tlc, then-wtf? Tail light looks a bit bright! Yup, brake light on. After some fiddling, I go to trusty Hyperstrada.com. That pesky micro switch wasn’t engaged with the adjuster screw! How long I been riding with it like this? I’m thinking months. Probs when I changed the lever height. Lucky I wasn’t *** ended.

gatdammit · Jun 24, 2021

first time this happened to me a nice motorists warned me at a stop light. I was grateful and troubleshot immediately. Feel good road story of the day.

RennyRacer · Jun 25, 2021

gatdammit said:
first time this happened to me a nice motorists warned me at a stop light. I was grateful and troubleshot immediately. Feel good road story of the day.

Did I miss something, but didn’t see this mentioned. The adjustment screw end has a hex opening making adjusting in or out very easy.

gatdammit · Jun 26, 2021

The spring they use in the factory system complicates a lot of things. Most aftermarket rearsets ditch the big return spring on the foot lever and it makes things much easier to R/R and adjust

JackAttack757 · Oct 31, 2021

@edgary
@zibbit u2
@RennyRacer
@gatdammit

You guys rock. My tail light was stuck on, quick search on the forum, two possible ideas, I run back to the garage and fix it in 30 seconds. It took longer to search the threads than to fix the issue.

the rear pin was not fully resetting, I adjusted the screw to make full contact with the rear plunger (switch) #10 and #7 above and it was a quick fix.

Whew...

gatdammit · Nov 1, 2021

Ya...I'm pretty awesome. Cheers and congrats. At some point in the future, you'll be asking yourself why your current issue couldn't be as easy to fix as that stupid rear brake light.

Keep this site alive with knowledge, no matter how insignificant. Can't say its the best but, we have some real shade-tree geniuses hacking away on their Hypers. RIP Kusksol...

appliance821 · May 24, 2022

Good info, but quick note: I'm pretty sure the the brake lights are leds.

nowayout · Nov 27, 2022

So is the little male end that comes in and out is it always supposed to be in contact with the plunger? I have tried both ways of adjustment and still no fix for me.

brake light stuck on

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