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*Warning* Brake Light Actuator (flashing ABS light)

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Hey all,
This is a continuation of a thread where I was asking about a flashing ABS light. Now that I know the cause, I thought it deserved a dedicated thread because it may impact you too.
The issue was that my ABS light would flash after a few minutes of riding. I then realized that my brake light was constantly on. So, the ABS system thought the wheels were turning while the brake was applied. After a few minutes of riding, the ABS light would flash because it's the only way the ECU can let you know there's a problem with the braking system (whether it's ABS related or not). In this case, the ABS was still functioning normally.
I dropped it off at the dealer, and they found the problem. There is a spring in the brake light actuator in the brake pedal assembly that was installed backwards. This was causing it to catch and hold the brake light on constantly.
The reason I had *Warning* in the subject line, is because the dealer checked all of the other FJ's they had in stock, and all of them had this spring installed backwards too. This could be a batch problem impacting a small number of bikes, or it could be all of them. My dealer has escalated to Yamaha Canada so they can investigate, but obviously riding without a functioning brake light isn't all that safe. The good news is, the bike at least gives you a visual indicator that something is wrong. FYI - My bike had about 1500 KMs on it when this happened.
Moral of the story, if your ABS light starts flashing, check that your brake light is working. If it's not, this may be why.
I wish I could provide full instructions to fix it, but I didn't see what they did and am not that technical. Perhaps someone else on here will fill in those details at a later time. Also, my description of the problem is just from memory of my conversation with the dealer. If I've stated anything wrong or called something by the wrong name, correct me :)
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Thanks FigJam09,
strangely, this part you speak of is a really old design. Most new bikes (European mainly) have micro switches. The switch body is threaded and a lock nut assembled at a set depth. The spring is simply a connection to the brake lever. Usually, the set depth of the lock nut will determine at which point the rear brake level will trigger the rear tail light. If it's too low (the switch body, in your case) the tail light is constantly on because it's pulling the spring wire. So, me thinks the switch is connected to the ABS module that it thinks the brakes are on and the module is showing a warning signal.
It also could be the plastic screw thread on the body is really weak and the threads slip from the lock nut.
It's an old design. Maybe that's why the bike is cheaper than everything else.
If somebody could post a photo, you will see what I mean.
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  • 2 months later...
Soooo.. My ABS light started flashing at me riding today. Continuous for the last 10minutes. Probably not a coincidence that I was testing the rear brake pedal force... I pushed hard enough to get this spring stuck?
- Oddly enough, my wife and I rode to dinner and no problem.
- Is this backwards spring easy to check and fix DIY?
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Well, I found my problem and it was user created.
- I had adjusted the brake pedal and didn't realize this was enough to trigger the brake switch full time.
- I just adjusted the rear switch for a little more slack and no more problem.  Pretty neat that bike's are getting smart enough to tell us when there's a problem!
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Call me crazy, but I was curious as to the construction of the rear brake switch. Literally, it's like one moving part (the center spring-loaded pin) and two contacts on either side of it. The pin is plastic with a band of metal wrapped around the middle that creates a circuit w/ the two contacts. The external spring connects the center pin w/ the pedal. Too much tension on the exterior spring pulls the pin down and makes a circuit with the contacts. 
- I didn't see any way possible to install either spring backwards....
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  • 3 months later...
beberle, thanks for this. I did the same thing. As an old MXer I hate my rear brake to be adjusted up so high. Once I adjusted it where I liked, the ABS light started flashing at me inconsistently. You saved me a ton of time and this is why I love forums like this. I will return the favor one day.  :)
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  • 1 year later...


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