Determining wiring for a multifunction led headlight

Thread Starter

eurban

Joined Feb 15, 2022
17
Greetings,
I have an LED headlight that has a 6 pin connector (only connector) on it. I want to safely determine how to wire it. It's from a 2021 Ducati motorcycle and there is no workshop manual (with wiring diagram) yet available for it. I know for certain that the light has the following functions: Low Beam, High Beam, and a halo style Daylight Running Light. Based on the markings on the back of the headlight there appears to be 4 functions that are given a wattage rating for. It is possible that there is a light sensor built into as the motorcycle will turn on and off the low beam (DRL always on) depending on the ambient light.

I am mostly interested in Low, High and DRL. I don't have the actual motorcycle to test voltage on so I am left with a complete mystery on how to wire it up.
What is the best practice for debugging this? I have access to a decent DVM and a 12v motorcycle battery. I have considered using a conventional 9 volt battery to experiment with which I would hope would allow the various features to light up while at the same time not being powerful enough to cause any damage. Any advice would be greatly appreciated.
Erics-l1600-1.jpg
 

Tonyr1084

Joined Sep 24, 2015
6,891
It appears the headlight shown by the TS and the same exact headlight shown in the link are absolutely identical. If the TS HAS this lamp in his possession I don't think it would be exactly the same as in the link. Especially the faded hand written 3221 at the top of the lamp in both photos.

eurban if you have the headlamp please take a picture of it and post it. There may be some different information on what you have that may prove helpful.
 

MrSalts

Joined Apr 2, 2020
1,762
It appears the headlight shown by the TS and the same exact headlight shown in the link are absolutely identical. If the TS HAS this lamp in his possession I don't think it would be exactly the same as in the link. Especially the faded hand written 3221 at the top of the lamp in both photos.

eurban if you have the headlamp please take a picture of it and post it. There may be some different information on what you have that may prove helpful.
An image search shows that he's posted this image and slight variations of his question on more than a dozen websites.
 

Thread Starter

eurban

Joined Feb 15, 2022
17
Everyone,
I have posted questions regarding this headlight on Custom Fighters and a Ducati forum with no really progress towards the goal of figuring out the wiring to it. The image in the picture is a handy one that I found on an overpriced Ebay listing for same type of headlight. I suppose that is why it is showing up in a number of places (that I have nothing to do with) on the internet. I now actually have a new headlight in my possession from anIMG-1371.jpg Ebay supplier in Italy. I will include a picture of it as well but it's not going to tell y'all anything more than I have already posted. For the detectives amoung you, would it help if I put next to it a clip from today's Washington Post?:)
Honestly, I'm a reasonable fellow just trying to figure out how to wire this headlight that I purchased so that I may use it on a custom project. . .
Does anyone have any suggestions on how to actually figure out the wiring of the headlight? Thank you.
 

MrSalts

Joined Apr 2, 2020
1,762
I would remove the fasteners circled in red, lift the bottom edge, slide down to release the back housing from the chassis. There may be more fasteners than visible. Then look at the circuit board. Take photos and post here if you cannot figure it out.
A0C88817-458C-400A-A73E-B321790AEB4A.jpeg
 

MrSalts

Joined Apr 2, 2020
1,762
Not even close sir. It's probably a good idea to understand something before you post!
You are the one posting on a thread that you started specifically about something that you don't understand. I'm not sure you are giving good advice, or if you are giving good advice, you are not following that advice.
 

Thread Starter

eurban

Joined Feb 15, 2022
17
I would remove the fasteners circled in red, lift the bottom edge, slide down to release the back housing from the chassis. There may be more fasteners than visible. Then look at the circuit board. Take photos and post here if you cannot figure it out.
View attachment 260830
There are more screws at the top as well. I have already removed all the visible fastener once and the unit didn't easily separate. It may well be sealed up with an adhesive but I will give it a shot with a bit more gusto tomorrow and post picture of the innards if separation is possible. Thanks.
 

Thread Starter

eurban

Joined Feb 15, 2022
17
You are the one posting on a thread that you started specifically about something that you don't understand. I'm not sure you are giving good advice, or if you are giving good advice, you are not following that advice.
Yes I am asking for advice yet you are claiming something that I know to be false at my expense. Since I know for a fact that have only posted my questions in two other locations, it seem obvious that you clearly don't understand whatever it is that you are basing your comments upon.
 

Ya’akov

Joined Jan 27, 2019
5,663
According to the data on the back the internal components use the regulated battery voltage. I would probably try test it first by using a DMM to work out what is common and what might be the LEDs. Then with a current limited power supply set to about 12V and about 20mA, I'd test from common to each pin and see what lights up.

There may be something on pin 6, or not. If I had to bet on it, I am going to say two of the pins are for the negative side and the other four are LEDs.
 

Thread Starter

eurban

Joined Feb 15, 2022
17
According to the data on the back the internal components use the regulated battery voltage. I would probably try test it first by using a DMM to work out what is common and what might be the LEDs. Then with a current limited power supply set to about 12V and about 20mA, I'd test from common to each pin and see what lights up.

There may be something on pin 6, or not. If I had to bet on it, I am going to say two of the pins are for the negative side and the other four are LEDs.
Thanks! So are you saying that based on the data on the back of the headlight that it is not likely to be a microprocessor controlled unit?
I have found the correct molex connector to mate to the 6 pins on the housing and I still need to crimp wires to the terminals and insert into the connector. Once I do that it will be easier to test the headlight. I can map out the resistances between all the wires and then have something to report back here. I'm not well versed in electronics testing so a bit of hand holding may be helpful once I have some data.
I am also not setup with a testing 12v power supply that I can limit current on but if I can determine which terminal(s) are ground that would seem to be a great starting point from which the risks of connecting up power to the terminals would be minimized.
As to the LED functions. I have carefully read the owners manual (and looked at walk around video reviews) for the Ducati Monster and the lighting for the headlight appears to only be Lowbeam, Highbeam, and the Halo which functions as a DRL. So the question is what the 4th item is that is listed on the back of the headlight. I was speculating earlier that it could be the daylight sensor that I also know the bike has somewhere on it since it automatically turns on the low beam when it gets dark out (DRL is always on). You can change this default setting in the dash control panel to always have the low beam on.
Anyways I'll report back with some details when I have them. Thanks again!
 

Ya’akov

Joined Jan 27, 2019
5,663
I expect two of the pins will have close to 0Ω resistance between each other and those will be a common negative. The others, being 13.5V rated diodes will probably start to light up around 10.5V but they will be very dim and you'll need to have low lighting to see it. The advantage of using the low voltage is it will be inherently current limiting and even if you somehow reverse bias the LEDs they won't be harmed.
 

Thread Starter

eurban

Joined Feb 15, 2022
17
Ok so I found a moment and did some testing. I started off with my digital meter but found it to be shifting though the resistance ranges too much. Things became clearer when I switched to my old large analog meter. One thing that I found odd is that I got different readings depending on the order of the black and red leads on the two pins I was testing. Here's what I found on 10k Ohm scale (O is open):
First list is with the black lead on the first number in the pair
1-2=7.5
1-3=O
1-4=O
1-5=O
1-6=11.8
2-3=O
2-4=O
2-5=O
2-6=11.8
3-4=O
3-5=O
3-6=O
4-5=O
4-6=49
5-6=O
Second list is with red lead on the first number in the pair
All O except
2-4=22

So there was no two posts that had almost no resistance between them. Post 1 has 2 resistance connections, Post 2 has 3, post 3 has 0, post 4 has 2, post 5 has 0 and post 6 has 3.
So what does it all mean (if anything)?
Thanks!
Eric
 

Ya’akov

Joined Jan 27, 2019
5,663
I am a little confused by your list.
What is the unit for the numbers? ohms, kiloohms?
Are the zeroes indicating a short, as in 0Ω or infinite resistance, as in the meter didn't move?
 

Thread Starter

eurban

Joined Feb 15, 2022
17
I am a little confused by your list.
What is the unit for the numbers? ohms, kiloohms?
Are the zeroes indicating a short, as in 0Ω or infinite resistance, as in the meter didn't move?
Scale is 10k ohms. O means open / meter didn't move
 

MrSalts

Joined Apr 2, 2020
1,762
A growing number of companies are just using two pins for +, two pins for - and two pins for canbus communication. Especially cars with DRL where the DRL has to turn off while the turn signal is actively flashing, integrated defrosters, multifunction headlight/fog-light, adaptive high beam, and whatever function manufacturers are integrating into the light.

The four wattage ratings are for high beam, low beam, DRL and something called POS. What is POS? How is it activated?

I think you need to retest the headlight with something more than an ohm meter. Your ohm meter may not be supplying enough voltage to over come three LEDs in series plus the current limiting circuitry inside. To do that, you'll risk damaging via reverse current but you can also cross your fingers and hope the unit has reverse current protection.

Alternatively, you can stop by your local Ducati shop and ask to see a manual on any current model with a six-pin headlight connector. The pins should be labeled. If two are data lines, you'll know you have a project if you are trying to put this on an older bike (either eliminating the communication boards inside or figure out how to communicate on the CANbus).

The joy of modifications.
 

MrSalts

Joined Apr 2, 2020
1,762
Hint, don't remove the bandage on the lower right. The headlight is sealed and a bag of silica gel is (likely) inside to control humidity in the housing. The "bandage" is a Gortex patch that allows the pressure in the housing to equalize as ambient temperature, self-heating and solar loading change.
 
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