Author Topic: K1 Brake Light on at all Times  (Read 3198 times)

Offline SteveMKentucky

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K1 Brake Light on at all Times
« on: July 22, 2013, 10:53:30 PM »
I'm working on a K1 that has had a number of problems.  So far I've solved an ABS light problem, caution light problem, inoperative fuel gauge and inoperative temperature gauge.  Each had a separate cause.

Now I discover that the brake light is on whenever the key is on and is unaffected by depression of the brake lever or pedal.  Is this problem related to the ABS?
59 NSU Maxi; 61 BMW R60; 61 Norton Manx; 66 BMW R27; 66 Triumph TR6R; 71 Norton Commando; 71 BSA B25 GP racer; 87 BMW R80; xx Triton (Norton/Triumph custom); 13 Harley FLHTK

Offline Scott_

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Re: K1 Brake Light on at all Times
« Reply #1 on: July 22, 2013, 11:05:34 PM »
Sounds like one of the brake switches is sticking.
Check both of the master cylinders and see of both are truly retracting fully.
Sometimes there can be some crud buildup behind the piston that prevents it from retracting far enough.

One way to check and see which one is the problem. Turn on the key, and watch the "brake light check" red indicator on the inst cluster.
With the light on, operate only one of the brake switches at a time. After only 1 brake switch test, you have to cycle the ign off/on.
The one that turns the light off, is not the sticking one....

If you still have a solid brake light after testing both switches, it could be the BMU unit in the electrical relay box.
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Offline SteveMKentucky

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Re: K1 Brake Light on at all Times
« Reply #2 on: July 23, 2013, 06:38:39 PM »
Sounds like one of the brake switches is sticking.
Check both of the master cylinders and see of both are truly retracting fully.
Sometimes there can be some crud buildup behind the piston that prevents it from retracting far enough.

One way to check and see which one is the problem. Turn on the key, and watch the "brake light check" red indicator on the inst cluster.
With the light on, operate only one of the brake switches at a time. After only 1 brake switch test, you have to cycle the ign off/on.
The one that turns the light off, is not the sticking one....

If you still have a solid brake light after testing both switches, it could be the BMU unit in the electrical relay box.

Thanks Scott.  Will check both out.
59 NSU Maxi; 61 BMW R60; 61 Norton Manx; 66 BMW R27; 66 Triumph TR6R; 71 Norton Commando; 71 BSA B25 GP racer; 87 BMW R80; xx Triton (Norton/Triumph custom); 13 Harley FLHTK

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