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Discussion Starter #1
It seems I have a faulty rear brake light switch. After riding the bike for a period of time the brake light stays on. I had to disconnect the rear brake light switch to make the brake light go out. It works fine when cold but at soon as the engine gets some heat the light stays on. Sometimes if you pump the rear pedal you can get it to go out but it soon comes back on. I'm not riding the brake and there's no sign of excessive rear pad wear. Also when the light is on you can easily spin the rear wheel so I believe I'm not having a brake problem. I found a posting in a search from a fellow who had the same problem about a year ago but since he was bringing the bike in for warranty he didn't post the outcome. Anyone else experience this? Are these rear switches a problem? Does the heat from the exhaust cause problems with them. Even though the bike is under warranty I would just as soon fix it myself as my dealer is in a location that would be difficult for me to get to until spring. For the time being I'll just leave the switch unplugged. Oh, about 2700 miles on a 07.
 

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Try giving it a few drops of oil and maybe adjust it a little, don't know for sure but I have never seen a rear brake switch that can't be adjusted.
 

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I would just bite the bullet & change it. Mine went at about 13000. Not a difficult job but getting the wires & plastic block through the new rubber boot is fiddly. You must fit a new boot as you have to cut the old one off & it will probably be perished anyway. !! The switch is not expensive. About $28 US.Use a pair of long nose pliers to stretch the boot to fit the wires through one at a time. Roll the boot back as far as you can & fit the plastic block which the wires fit into to make them plug in together. Make sure you note how the block comes off. It only fits properly one way !! Have fun.
Chris
 

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Discussion Starter #4
Replace the switch today. Not the easiest thing to get to, it took a few hours taking my time including bleeding the rear brake. There was no need to cut off or replace the rubber boot, so I'm not sure what the above poster means. One very interesting note, the old switch is very temperature sensitive. I did a continuity test using an ohm meter. At about 85 degrees F the switch goes in the on position, below that it stays in the off position. Hard to understand way a stop light switch is so temperature sensitive.
 

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Could be you got a switch with very tight tolerances and when it gets hot the metal expands and makes contact. Just guessing here but wouldn't be surprised if that's what happened.
 

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Replace the switch today. Not the easiest thing to get to, it took a few hours taking my time including bleeding the rear brake.
I have the same problem. Only seemed to start during my 2,500 mile trip round Spain last month. Now it comes on after a few miles. I have done approx 10k miles.

Please can you confirm where it is - I think that it is fitted above the master cylinder. Do you have to remove the fuel tank and rear fairing? I have ABS - will that make a difference?

TIA
 

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Yes, it is located on top of the rear brake master cylinder.

Yes, ABS increases the difficulty, but nothing major.

No, you do not need to remove the fuel tank, nor the fairing. In your case, you will need to remove the ABS dust shield.

Depending on your tools, it can be unscrewed from the master cylinder with the cylinder in place. You might have to disconnect and remove/reposition one ABS hard line.

If you do not have the tools to remove it with the cylinder in place, it is only a matter of two fasteners, and the associated linkage and plumbing to remove the master cylinder.

If care is taken, you could probably get by without bleeding. But, if I were doing it, I would opt for bleeding with the Triumph gameboy.

You also may as well plan on replacing the rubber boot while you are at it because they seem to be the same grade rubber as the relay holders.
 
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