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Ähem: I say: P.S.: light blue is a dead end as far as I can see because there is no pin on the male plug on the Headlight between the ones connecting to purple and brown
 

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I'm just a girl in her garage with no fancy degrees and a willingness to think outside the box.

You need a 39ohm 10w resistor on the DRL wire to ground.

That's literally it.

You can type 39ohm 10w resistor in Amazon and find them for sale.

You then need an H4 pigtail from somewhere like motodemic.

Ground goes to ground.

Low beam wire to low beam on the pigtail, high to high.

It's dead easy, you just can't be defeatist. You just have to get out there and figure out what wire is which

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You once wrote in the german BMW Bike Forum: "I only needed a resistor for the DRL light, a 39Ohm resistor. I tried 10w, but it gets very warm, I'll change to a larger 25w resistor so it can handle the heat better." Did you try the 25w resistor or was there no need for it anymore?
 

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10w had been fine, but the bike hasnt been ridden in like two months due to no exhaust system on it, and waiting on Cobra SpeedPro to ship my new system which was ultimately lost by DHL

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Also low and high beam are both on at the same time, that's probably why the harness is like that

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Mark – 2015 R1200R-LC Exclusive
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I'll change to a larger 25w resistor so it can handle the heat better.
The heat is generates through the dissipation of energy as electrical current passes through it. The wattage rating relates only to how much power the resistor is designed to handle without failure. So changing to a resistor of higher wattage rating will make no difference to the amount of heat generated.
 

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The wattage rating relates only to how much power the resistor is designed to handle without failure. So changing to a resistor of higher wattage rating will make no difference to the amount of heat generated.
Good point. So - as TheDivaDanielle also said: 39 Ohm 10W be it!
 

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So changing to a resistor of higher wattage rating will make no difference to the amount of heat generated.
But it will have a lot to say about how hot the resistor gets.
 

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Mark – 2015 R1200R-LC Exclusive
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But it will have a lot to say about how hot the resistor gets.
Um, not really, except for the resistor's ability to radiate the heat generated in use (via a larger surface area or perhaps heat sinks for higher rated resistors).

V=voltage (volts)
R=resistance (Ohms)
I=current (Amps)

I=V/R
Power=VI=V*V/R

Heat is generated by the power the resistor is absorbing, so the amount of energy (heat) is the same regardless of the resistor's power handling rating. As per the formulae, only the resistance (R) and supply voltage (V) are relevant, not the rating of the resistor.

The rating of the resistor needs to be sufficient to cope with the power it is turning into heat so that it doesn't burn out internally. A lower rated resistor is likely smaller than a higher rated resistor, so because of its lower mass it will increase temperature quicker, and perhaps radiate that heat slower, but they both absorb the same amount of energy and hence produce the same amount of heat.
 

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Um, not really, except for the resistor's ability to radiate the heat generated in use (via a larger surface area or perhaps heat sinks for higher rated resistors).
The power rating of a resistor is usually directly connected to its ability to get rid of the heat, and thereby how hot it gets. Radiation is not the main heat transfer mechanism, conduction and convection are usually more important when mounting a power resistor on a motorcycle.
 

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Mark – 2015 R1200R-LC Exclusive
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I think we’re in agreement then, @ogee. I was figuring the resistor would be placed within the (plastic) headshell, where there’s not much opportunity for conduction, but I was a bit loose in using just the term radiate.

I was thinking of the regular wire-wound resistors from your local electronics store, where a 5W is the same form as a 10W but for size, but a ‘CANBUS error resistor’ is probably what others have in mind - with heat sink.

108039

108040
 

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Mark – 2015 R1200R-LC Exclusive
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OK, it’s time to ‘fess up. Anything I’ve posted about Headlight Pro has been based on assumptions and logic - which are both clearly flawed and without foundation (I could exaggerate, and say I was wrong ... 😅).

Curiosity got the better of me and I pulled the headlight off to do some testing. The six-pin connector has one position vacant, one for earth, and one each for high and low beam, then two for the Daylight Riding Light. The GS circuit diagram in the Haynes manual shows three leads to the DRL, two positives and a ground - just as on the Roadster.
108051


One of the DRL leads from the bike side measures battery voltage and the other 80% of battery voltage. Given it’s driving an LED array, I expect the latter is battery voltage that is pulse modulated at an 80% duty cycle. Connected to the bike, though, I could not produce a condition where the DRL varied in brightness - it seems to remain at the one intensity. Puzzling.

One would expect, then, that applying 12V across the DRL’s earth and higher voltage terminal would create light - but no. Similarly with the modulated lead, and even both together. No, I didn’t get the polarity wrong.

I put the headlight back on the bike, none the wiser (but thankfully it still worked). In fact I was even more confused than before.

I’ve come to the conclusion I know nothing about how the DRL actually works, but I expect if dispensing with it to fit an alternative headlight, a load will need to be applied to both input leads to avoid a LAMP error. But I could be wrong ...
 
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One would expect, then, that applying 12V across the DRL’s earth and higher voltage terminal would create light - but no. Similarly with the modulated lead, and even both together. No, I didn’t get the polarity wrong.
Interesting!

Could it be that pins 1 and 3 are power and control to an LED driver circuit? If the control pin requires a pulsed signal it would explain what you observed. I don't see why BMW should make something like that, but that wouldn't be the first time.

Would be interesting to get confirmation that the 80% voltage is in fact a modulated signal. You don't happen to have an oscilloscope?
 

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Mark – 2015 R1200R-LC Exclusive
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Unfortunately I don’t have an oscilloscope, ogee, so have no way to decode this Bavarian wizardry. 🧙🏻‍♂️

The original objective was to measure the current through each circuit to objectively determine the resistor values that might be used if the headlight was replaced with an alternative item. Looks like this would need to be done on the bike via the rear connector.
 

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Connected to the bike, though, I could not produce a condition where the DRL varied in brightness - it seems to remain at the one intensity. Puzzling.
At my (european) bike the LED-unit has two modes: DRL and position light. The latter probably has much less power consumption than the DRL. Maybe that's the difference?
 

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Unfortunately I don’t have an oscilloscope, ogee, so have no way to decode this Bavarian wizardry. 🧙🏻‍♂️

The original objective was to measure the current through each circuit to objectively determine the resistor values that might be used if the headlight was replaced with an alternative item. Looks like this would need to be done on the bike via the rear connector.
It's Berlin wizardry, by the way. BMW-Bikes are not build in bavaria. Maybe that's an explanation for whatever there's going on : - )

But beside the LED-Unit mystery: did you determine the resistor values to use if replacing the 55W high and low beams?
In the case of my favoured full-LED headlight they would be replaced with a 1,3 / 16W high- and a 1,8A / 22W low beam? (as they say in the data sheet)
When I tested it, I got the LED-Unit to shine at first step (= turn on the electric circuit / dashboard on) and the low beam and an error message at the next (= starting the engine)

To return the favour of hopefully answering my last question I give you pictures of a 6-pin connector I finally found and which I hope enables me to connect whatever will work without changing the one coming out of the bike. You have to reshape one of the corners a little bit but then it should do the job of a secure connection in at least IP54 quality.
20200615_114804_resized.jpg
20200615_120254_resized.jpg
20200615_124836_resized.jpg
 

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Mark – 2015 R1200R-LC Exclusive
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It's Berlin wizardry, by the way. BMW-Bikes are not build in bavaria.
Ah, but the elves of the Black Forest are consulted, and we all know elves belong to a wizard.

On your resistor question, assuming an H7 bulb runs at 55W at normal operating voltage (14.2V rather than the nominal 12V) then it draws 3.9A. Subtracting the spec current draw of the LED high and low beams gives a residual 2.6 and 2.1A respectively. At 14.2V, this requires a 5.5 and 6.75 Ohm resistor respectively for high and low beam in order to atch the stock bulb. I'd suggest 6 Ohm would be close enough for both beams.

The power each resistor will dissipate at 6 Ohms is 34W, so a 50W resistor rating would be safe. Something like this one:
108068
 

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OK, it’s time to ‘fess up. Anything I’ve posted about Headlight Pro has been based on assumptions and logic - which are both clearly flawed and without foundation (I could exaggerate, and say I was wrong ... ).

Curiosity got the better of me and I pulled the headlight off to do some testing. The six-pin connector has one position vacant, one for earth, and one each for high and low beam, then two for the Daylight Riding Light. The GS circuit diagram in the Haynes manual shows three leads to the DRL, two positives and a ground - just as on the Roadster.
View attachment 108051

One of the DRL leads from the bike side measures battery voltage and the other 80% of battery voltage. Given it’s driving an LED array, I expect the latter is battery voltage that is pulse modulated at an 80% duty cycle. Connected to the bike, though, I could not produce a condition where the DRL varied in brightness - it seems to remain at the one intensity. Puzzling.

One would expect, then, that applying 12V across the DRL’s earth and higher voltage terminal would create light - but no. Similarly with the modulated lead, and even both together. No, I didn’t get the polarity wrong.

I put the headlight back on the bike, none the wiser (but thankfully it still worked). In fact I was even more confused than before.

I’ve come to the conclusion I know nothing about how the DRL actually works, but I expect if dispensing with it to fit an alternative headlight, a load will need to be applied to both input leads to avoid a LAMP error. But I could be wrong ...
Non US bikes have a DRL circuit intact and US bikes still got the same headlight without the functionality. Headlight on - reduced DRL, headlight off - full DRL.

I swapped my switchgear because I had a sticky button, and got a euro spec one, I could control my DRL brightness with a button push, but since I have a US bike I can't turn it off.

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OK, it’s time to ‘fess up. Anything I’ve posted about Headlight Pro has been based on assumptions and logic - which are both clearly flawed and without foundation (I could exaggerate, and say I was wrong ... ).

Curiosity got the better of me and I pulled the headlight off to do some testing. The six-pin connector has one position vacant, one for earth, and one each for high and low beam, then two for the Daylight Riding Light. The GS circuit diagram in the Haynes manual shows three leads to the DRL, two positives and a ground - just as on the Roadster.
View attachment 108051

One of the DRL leads from the bike side measures battery voltage and the other 80% of battery voltage. Given it’s driving an LED array, I expect the latter is battery voltage that is pulse modulated at an 80% duty cycle. Connected to the bike, though, I could not produce a condition where the DRL varied in brightness - it seems to remain at the one intensity. Puzzling.

One would expect, then, that applying 12V across the DRL’s earth and higher voltage terminal would create light - but no. Similarly with the modulated lead, and even both together. No, I didn’t get the polarity wrong.

I put the headlight back on the bike, none the wiser (but thankfully it still worked). In fact I was even more confused than before.

I’ve come to the conclusion I know nothing about how the DRL actually works, but I expect if dispensing with it to fit an alternative headlight, a load will need to be applied to both input leads to avoid a LAMP error. But I could be wrong ...
No, just the one.

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