Sachs Prima G3 -brake light on, when I pull hand lever the brake light turns off

I'm trying to figure out why when the hand brake is at rest, the brake light is illuminated and when the hand brake lever is pulled, it turns the brake light OFF. Ass-backwards, as they say.

The foot brake activates the brake light when pressure is applied (as it should). (To test the foot brake light, I pull the hand brake lever so the hand brake switch button is popped up and the brake light is not on (again, ass-backwards from what it should be), then, with the brake light not illuminated, I apply the foot brake and the brake light turns on as it should.) Based on this, it would seem the problem is somewhere in the switch or the wiring to the hand brake lever.

Any idea where to start? Thanks a bunch.

Re: Sachs Prima G3 -brake light on, when I pull hand lever the brake light turns off

Sounds like you have the wrong brake switch in your lever assembly.

Magura controls?

You probably need this one:

https://www.treatland.tv/brake-light-switch-p/brake-light-switch-magura.htm

Re: Sachs Prima G3 -brake light on, when I pull hand lever the brake light turns off

Is the bike new to you? Has it worked fine before and this has just happened? Have you done any work on it lately that could affect it?

Re: Sachs Prima G3 -brake light on, when I pull hand lever the brake light turns off

It was worked on before it came to me. Many problems were solved when I had an electrician friend re-wire it according to the schematics and then I put in the proper tail light (which requires a resistor) and everything but the hand lever brake switch is working.

This bike requires an NO (normally open) switch. When in its relaxed state (lever puller; with the button popped up) there should be no continuity. But there is. Maybe there is a NC switch in there?? Unless I don't understand the workings of NO and NC switches (which might be the case), this sounds like the problem.

I'm not an ohm meter expert, but I did a continuity test and when in its relaxed state (lever puller; with the button popped up), there is continuity. With the button depressed, there is no continuity. This is backwards from what it should be.

From: https://www.mopedarmy.com/wiki/Electrical

"N/O and N/C which is normally open and normally closed, this refers to the continuity between the contacts when the switch is at the rest position. ( N/O electricity does not pass when at rest ). ( N/C electricity does pass when at rest) . this can lead to some confusion as at rest can be different when installed. "

Do y'all think I have my head around this properly?

Re: Sachs Prima G3 -brake light on, when I pull hand lever the brake light turns off

Why did you start another thread ?

Re: Sachs Prima G3 -brake light on, when I pull hand lever the brake light turns off

It sounds like you do have the correct switch and are thinking about it backwards.

When you're NOT using your brake the lever will rest against brake switch pushing the button IN. This should BREAK continuity so there your brake light is OFF.

When you ARE using your brake the lever will no longer rest against the brake switch meaning the button is OUT. This should ALLOW continuity so your bake light is ON.

Based on what your saying you have the correct switch.

Unless your controls operate differently than normal Magura controls.

Post a pic of your controls w/ the brake switch.

Re: Sachs Prima G3 -brake light on, when I pull hand lever the brake light turns off

I'll tell you straight up that electrical whatnot makes my head spin. I greatly appreciate the feedback and intel, spudley. The Prima G3 has some weird built in oddities, like the resistor in the brake light assembly that, if you don't have, will kill the engine if a bulb burns out. So it might be that the quirks are more about the bike's wiring than the brake control workings. I do know the Prima G3 takes a N/O (normally open) switch.

From the wiring diagram:

"RH Brake light Switch

Switch is a NO type (normally open ) in it's relaxed state (Position when brake lever is squeezed). When the brake lever is not being squeezed, a ground connection travels thru the switch which grounds out the black w/red wire."

When I put the multimeter on the switch that is currently in there to test for continuity, these are the results:

button up = continuity

button is pressed in = no continuity

So when I pull the brake lever it creates continuity. When I release the lever, no continuity.

I'm a Luddite about electrical so, in an attempt to better understand, I went here:

https://www.theautomationstore.com/electrical-contacts-normally-open-and-normally-closed-contacts/

"We close an electrical contact to start current flow and we open an electrical contact to stop current flow."

Closed = Current flow

Open = No current flow

So I need no flow when the brake lever is pulled (popping up the button) and I need flow when the brake lever is released (pushing the button in). Is this right? And does "continuity" = "flow"?

*head explodes*

Thanks again!

Re: Sachs Prima G3 -brake light on, when I pull hand lever the brake light turns off

So unless I have it all backwards, maybe I need this:

https://www.treatland.tv/magura-clutch-switch-black-p/magura-clutch-switch-blk.htm

"magura plastic clutch switch / button. use on most all magura assemblies that accept these + most domino assemblies too. comes with rubber cover and two terminal wire connectors

1/4in threading x 6mm long

off in paused position

this is a less common type of switch. there is basically no power or connection in the switch unless the button on the switch is pushed in. this will be when your lever is closed - so when you aren't pulling the lever, the connection in the switch is bridged and power is being distributed. when you actually pull the lever, the button on the switch is no longer being pushed in and then the connection is no longer bridged and no power is flowing.

some mopeds have wiring that need this type of switch, so if you need it, we got it!"

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