Brake switches

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I've noticed that there is a continuous draw of about half a volt at the brake light contact when I connect the wires to the front brake switch. The other interesting clue is that there is a difference in voltage at the brake light contact on the harness just before the light fixture when I pressed the rear switch vs the front switch. Rear brake switch sends about 12.1 volts to the rear connector at the fixture, while the front switch is sending about 11.4.
 
Supercat said:
I've noticed that there is a continuous draw of about half a volt at the brake light contact when I connect the wires to the front brake switch. The other interesting clue is that there is a difference in voltage at the brake light contact on the harness just before the light fixture when I pressed the rear switch vs the front switch. Rear brake switch sends about 12.1 volts to the rear connector at the fixture, while the front switch is sending about 11.4.
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you might have some corroded connections or wiring from your front switch.
 
Supercat said:
I've noticed that there is a continuous draw of about half a volt at the brake light contact when I connect the wires to the front brake switch.
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Measured between the brake light (bulb holder?) contact and ground?

I also get a reading of just over half a volt between the bulb contact and ground (bulb removed) with the system otherwise working normally but 0.0 amps so it seems there is no 'draw'.
 
Finally found a few minutes to get back out to the shed. Looks like I've got a diagnosis: a loose connection under the tank. The stop light is now working when I use the front brake :). I'll still need to replace my rear brake switch, but I've got that temporarily sorted also and, theoretically, she should be all set for inspection.

Thanks again for all the help lads!!!
 
Supercat said:
Finally found a few minutes to get back out to the shed. Looks like I've got a diagnosis: a loose connection under the tank. The stop light is now working when I use the front brake :). I'll still need to replace my rear brake switch, but I've got that temporarily sorted also and, theoretically, she should be all set for inspection.

Thanks again for all the help lads!!!
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Good for you. I have a recommendation regarding replacing the rear brake switch. There are alternative designs (micro switches, etc) but I've found that the stock OEM style works well and lasts a long time - except that the rear brake return spring sometimes isn't strong enough to push the button down and turn the light off. There is an aftermarket spring that wraps around the brake lever which makes that problem go away. It also keeps the brake lever from pivoting downward in the event that your brake cable breaks.

https://www.classicbritishspares.com/products/norton-brake-saftey-spring
 
Thanks maylar, and that's a great recommendation! I think I'll get one of those as I don't currently have a backup if the brake cable fails, and because of the switch issue you've ided.
 
My orginal rear brake light switch lasted for over 34 years and the replacement switch lasted 3 years and the last one I replaced it with even less time, I ended up replacing the switch off a old Honda dirt bike I had laying around and connected the spring to the brake peddle, works a treat, the replacement switches thats the same style of the orginal one just fell apart in the guts and the rubber cover just perished, the Honda switch was easy to mount making a small mounting bracket that mounts to the foot peg mount, took me about 15 minutes to mount up.

Ashley
 
ashman said:
My orginal rear brake light switch lasted for over 34 years and the replacement switch lasted 3 years and the last one I replaced it with even less time, I ended up replacing the switch off a old Honda dirt bike I had laying around and connected the spring to the brake peddle, works a treat, the replacement switches thats the same style of the orginal one just fell apart in the guts and the rubber cover just perished, the Honda switch was easy to mount making a small mounting bracket that mounts to the foot peg mount, took me about 15 minutes to mount up.

Ashley
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My original one went about the same, and the 2nd one is about 10 years now. Rubber boot still intact.
 
Thanks Ashman and Maylar. The one that I have with the rotted rubber was on there when I got the bike, but I didn't notice the condition of it until I put the light fixture on. I'll probably try one more actual Commando switch first, just to keep things as original as I can, but if it doesn't last long I'll explore some new options, like the one you mentioned Ashman. I've got the old one rubber cemented and hockey taped together until I get a new one in :). The top hasn't fallen off onto the road again so far anyway, lol.
 
Craig said:
I’m pretty sure I have a new front switch which is not needed since I went the CNW m/c route ... on Cape Breton Island right now , will take a look on Tuesday once home ... will be more than the other parts I sent earlier , haha!, still cheap though ...
Craig
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Craig, I wanted to thank you especially for the kind offer, and again for the help last year. The parts you sent me are still in use and I expect they will be for a long time to come. I'm still blown away that you did that. Definitely inspired me to get things done on the bike and it was a great reminder of how thoughtful and generous our species can be.
 
No worries Jamie , enjoy ! .... let me know if you want me to take a look for brake switches , have a good one !
 
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