daveyson wrote:What hi and low have in common is a switch powered from the right handlebar connector through a white/yellow wire, except I think in the US,  where it's probably bridged. The flasher gets power from the green/blue wire at the left handlebar connector.

I'd look at the right hand connector, at the green/blue and white/yellow wires.

robmack wrote:Don't know if this helps or not.  The schematic below shows the two possible configurations for the right hand switch cluster.



The dotted illustration on the left is the cluster complete with the Euro switch. Although it is labelled UK Only, I believe most European countries, and possibly most of the world markets for BMW, had these switch clusters installed.  For the US / Canadian markets, that switch was eliminated and the contacts were jumped.  You can see these in the same diagram as solid lines connecting Pins 4, 7 and 3.  This way, it was not possible to turn on and off the headlamp in these markets.

jjefferies wrote:

Hey thanks and an interesting lesson that it's the US and Canada that legislated that M/C headlights have to always be on.

daveyson wrote:Good to see it was an easy fix. This reminds me I wanted to do the headlight relay upgrade too. It's probably because I rarely ride at night that it's near the bottom of my "to do" list

jjefferies wrote:

daveyson wrote:I wouldn't say easy. Just straight forward. Did some shopping. The eastern beaver is a fairly expensive solution, approx USD $70. Though I do like the fact they use "Japanese" relays. Then I found this site: https://www.tomsbroncoparts.com/product/Heavy-Duty-Headlight-Wiring-Harness-66-77-ford-bronco-new?gclid=CjwKCAiA_9r_BRBZEiwAHZ_v15yE44v4u4vjhIOr5ct_ZHMEydJga1wwaD6JkMsQAKl4MLkmQM0AKBoCi74QAvD_BwE

Which does a somewhat similar solution for Bronco's but at USD $30. instead of $70. Being a president of the CABOA, I might lean toward this solution. Though considering how many relays I have in the garage, I might just check those out as well.

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robmack wrote:The Bronco harness is over-kill. It has one extra set of H4 connectors that will need to be eliminated or ignored.  The wire lengths are probably very long and you'll have extra wire to hide.  The schematic they provide is not detailed enough to determine if it will work properly so there is a risk right there.  The Eastern Beaver harness is proven.

Your choice with the Bronco harness but make sure you can return it if it doesn't work out for you.

jjefferies wrote:Thanks Daveyson, comments about the UK only on/off switch was the clue that got me looking at the schematics again. Still turned out it was the switch. According to another friend, Lee Fulton, it's not an uncommon problem. Particularly if you run a higher wattage bulb. But the little electrical contact buttons in the switch get hot and sort of melt back into the plastic reducing the contact and eventually causing the switch to fail. When I finally determined which leads were involved (white with yellow stripe(feed), white (hi beam), yellow (low beam), and measured the respective resistances the hi beam was 980 ohms and the low beam was infinite. So another switch is needed and then adding on one of the Eastern beaver relay systems will be the final solution.

Thanks guys.

What i see here is 'higher wattage bulb'. Anytime I add something which will draw more current than stock I add a relay. Contacts in handlebar switches are tiny & marginal at best for original loads, Relays are cheap.

1990k75 wrote:

What i see here is 'higher wattage bulb'. Anytime I add something which will draw more current than stock I add a relay. Contacts in handlebar switches are tiny & marginal at best for original loads, Relays are cheap.

jjefferies wrote:Which BTW, brings up another subject for inquiry, bar end weights. I have them on Red and there always seems to be a problem with the right hand (throttle) side due to interaction between the power feed and the  mechanism for mounting the bar end weight. Any thoughts/comments on the usefulness of bar end weights and their fitting out with heated hand grips?

jjefferies wrote:

1990k75 wrote:

What i see here is 'higher wattage bulb'. Anytime I add something which will draw more current than stock I add a relay. Contacts in handlebar switches are tiny & marginal at best for original loads, Relays are cheap.

I'd like to toss out two ideas that I'd appreciate your comments on:
1.) Use of an LED H4 headlight. Would that not also reduce the possible failure due to heating of the switch?
2.) How about use of some of the same type relays we have in the bucket under the tank? My count just now I have 23 of the various relays used on K bikes and that's not counting the ones in my parts bike. Yeah, I've had a few bikes and parts machines etc over the years. But surely a couple of those could be used as light relays. I've been of the opinion that they last for ever. Just thinking about repurposing rather than buying more.

I find it strange that I've never before encountered this problem of the headlight switch going bad due to heat. My Red K75 has 164,000 miles and no problem there. Though the same cannot be said of its heated hand grips. Left hand is too hot to hold and the right is freezing. That's my current project and will undoubtedly have it fixed in time for summer riding    Which BTW, brings up another subject for inquiry, bar end weights. I have them on Red and there always seems to be a problem with the right hand (throttle) side due to interaction between the power feed and the  mechanism for mounting the bar end weight. Any thoughts/comments on the usefulness of bar end weights and their fitting out with heated hand grips?

1990k75 wrote:
In my opinion (& Robmack knows way more than me) it's not 'heat' that causes switch failure, it's the amperage. For sure an LED option will draw way less current, but may complicate things because the LED 'bulbs' have heat problems - which is why they have heatsinks on them.