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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: pc759 on August 05, 2025, 10:39:29 AM
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Hello again everyone. I’ve a problem that I can’t seem to figure out involving an after market headlight and Speedo - yikes!
The problem is this everything works but the high beam. When I press high beam to on on the left hand switch it kills low beam same happens when I presss the flash button too so high beam isn’t on at all and when turned on it kills low beam. Can anyone advise? I’ve had the lbs switch off and cleaned it but am not sure how to determine if it’s a switch problem or elsewhere. There is continuity between lamp power yellow white and the blue green when I depress the flash button too
Any advice gratefully received
Thanks in advance
Paul
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Did you take the switch apart completely—buttons, springs, pins, etc.—to clean burrs and defects off the switch contacts?
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Yes did that la itch but not sure how effective it was tbh.
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Yes did that la itch but not sure how effective it was tbh.
If it was effective, you likely would have high and low beams that worked as designed right now. :laughing4-giggles:
It could be time to reveal what brand and model of speedo, headlight, and other related aftermarket gear you've installed. Maybe somebody around here had success installing them.
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I may be way off base here, but if you have power and ground to the headlight socket you could be looking at a defective bulb. I haven't seen in the thread so far that you've checked that. I've seen bulbs where the filament looks fine but that portion of the bulb doesn't work. If it is an LED I really don't know how to check that.
I can't say for sure, but I think the low beam cuts off when the high beam is on. If that is the case your system might be working as it should with a bad bulb.
Frank
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What often happens in a faulty OEM headlight switch is when an attempt to activate the High beam is made, the headlight shuts off altogether and then, maybe, the High beam turns on. There could possibly be a couple of exciting seconds until the light is turned on when switched between Low and High or High and Low. Sometimes, there is no pause between High and Low. Sometimes, the headlight activation depends upon the amount of pressure on the button; other times there's no telling when it will turn on.
Is that what's happening, pc759?
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I may be way off base here, but if you have power and ground to the headlight socket you could be looking at a defective bulb. I haven't seen in the thread so far that you've checked that. I've seen bulbs where the filament looks fine but that portion of the bulb doesn't work. If it is an LED I really don't know how to check that.
I can't say for sure, but I think the low beam cuts off when the high beam is on. If that is the case your system might be working as it should with a bad bulb.
Frank
from his post it sounds like the regular high beam switch works but not the flip up to flash so it sounds like a switch issue.
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If you open up the switch and one of these two contacts is worn or has heated up enough to recess into the plastic than that's your issue;
(https://i.imgur.com/IBO4yHk.png)
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Thank you all it is complete no high beam it works directly from battery though so no bulb problem I’ve seen that switch thread and tried to copy the cleaning tips . The Speedo is that cheap istozz one that’s on quite a few Kubrick projects the problem was the loom was cut when I got the bike. I’m getting close to completion just this problem to solve and I can put it forward to get it back on the road 48000 mile been off road for five plus years a German import into the uk !
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Here's a way to wire relays so that even if you headlight switch goes out you will always at least have a low beam;
(https://www.kbikeparts.com/classickbikes.com/ckb.tech/0.ckb.tech.files/hl.relays/Alt.Headlight.Relays.Low.Beam.V2.02.jpg)
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Thank you very supportive much appreciated