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Discussion Starter · #1 ·
I have a 500e that I've just installed LED headlights, DRL, and reverse lights.
Just as a quick note, the 500e uses the same control for lights as all the other 500 models.
This started with needing to replace a semi-melted reverse light lense and a completely out driver side headlamp. (the old incandescent lights)
I purchased all the lights from reputable sources.
The headlamps were from DiodeDynamics and work awesome once the headlights were adjusted properly. This was done using standard SAE protocol, however I found the lights worked better if adjusted slightly lower than they are supposed to be. No flashes from oncoming drivers, and you can see far enough ahead. High beams were aimed perfectly.

Other than that the LED lights work fine except for two problems: Error codes and the DRL's misbehaving.
The DRL's just flicker a very low output in the usual DRL mode. If the headlights are turned on, the DRL's shine like one would expect a of a DRL.
The instrument cluster warnings say I have no lights wherever I used an LED.

Ok, the standard "fix" is to place a 6 Ohm to 8 Ohm high power resistor across the light. I guess one could say that works, if you're willing to accept the compromises.

I looked at the OBDII error codes associated with the Body Control Module. Here's where it gets interesting.
Every LED light had this (or very similar) error:
B16D3-13 Right DRL Lamp Control Overcurrent

Overcurrent?? Everyone with any electrical knowledge knows LED lights use far less current than incandescent lights. If I add resistors across the LED's, the error might go away, but the reality is the circuit will have much more current than one with just an LED.

Thoughts?
 

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I had a big research of 500E's BCM module, its switches and algorythms.


The DRLs in 500 are powered not by "pure" DC, but with 100-Hz pulse with 80% duty cycle. It's OK for incandescents (though they don't heat up to their nominal temperature and give yellow light). And for many types of LEDs this is not acceptable.

This can be solved by hacking the "Intelligent switches" in the BCM unit. But, it's a kind of jewelry work...
 

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Discussion Starter · #3 ·
The DRLs in 500 are powered not by "pure" DC, but with 100-Hz pulse with 80% duty cycle. It's OK for incandescents (though they don't heat up to their nominal temperature and give yellow light). And for many types of LEDs this is not acceptable.

This can be solved by hacking the "Intelligent switches" in the BCM unit. But, it's a kind of jewelry work...
Hello GrayCat! Thank you for your information - this is huge. I've done a bunch of SMD work for other projects. This should be possible.

I have installed LED DRL's, and also found them "pulsing" at high frequency. They also seem to turn on and pulse for about 1 minute every 15 minutes even when then car is off and idle (not charging/unplugged). The LED DRL's really need to be 100% on to be useful.

What are the "intelligent switches" you are referring to? Are they darlington arrays? Do you have their part #'s?
Did you change their driver frequency somehow? Or did you change them to simpler on/off switches, maybe something with this pic:
Deceiver_01.JPG

Do you know how the microcontroller senses current in this circuit?

Would it be better to change the output or maybe change the input so it doesn't pulse??

I'd love to find a solution for this that actually solves the problem; rather than bandage it with a big resistor.

Sorry about my questions - I can't read Ukraine - this is really impressive work! :cool:
 

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Discussion Starter · #4 ·
Would the "intelligent switches" you are referring to be the Infineon BTS5242 switches like the wide ones you show in this pic?
F500E_BCM_09.JPG

Have you found all the lights to be controlled by these (except, maybe the headlights)? I get the same warnings about overcurrent for the DRL, backup, and front signal lights.

Also, I got some good schematics and pinouts for the car (not the BCM) that show the wiring & pinouts for the BCM. This might help.
 

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What are the "intelligent switches" you are referring to? Are they darlington arrays? Do you have their part #'s?
These are "BTS5231", "BTS5236", "BTS5242", "BTS5246" for different cirquits -- DRLs, "parking lights", "Turns", "Stop-lights", "Rear", "Side markers". Different currents => different detection thresholds. Read the datasheets for these ICs. Positively NOT "Darlington arrays" :) .

Do you know how the microcontroller senses current in this circuit?
I think, MCU's ADCs read the value given by "detection" outputs of the sitches. AND, especially in the case of DRLs, MCU expects this voltage to be of the same "square" pulse form as the driving' signal. So, I had to make one part of my "deceiver" to convert 100-Hz pulse to the constant signal to drive the lamps. and yet another part of it to give the same 100-Hz "feedback" to the MCU.
 

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Discussion Starter · #6 ·
OK! So this looks a bit more complicated...
I Got the datasheet for the BTS5242; it seems to be a discontinued Infineon part. Do you know if they just changed part numbers to something else?
I'm looking for some better info about the current sense part.
 

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Discussion Starter · #7 ·
So I decided to catch up w/ today's tech a bit & try Google Translate.
I also found this newer app note/ data sheet that helped out a bit:
GrayCat - this is very impressive work. I have a much better understanding of your work now.
Would you mind if I post the translated version (edited - lol :p) So that people can see in your words what you did?
Also - I would be interested in purchasing/ helping to develop a board to do what you did.
 

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Would you mind if I post the translated version (edited - lol :p) So that people can see in your words what you did?
Well, it's just my lazyness to not translate it myself ;-)

Also - I would be interested in purchasing/ helping to develop a board to do what you did.
The problem is not in the additional board. It's just a bunch of emitter followers. The main problem is that we have to "replace" several signals on the BCM board, and we have two ways to do that:
  1. Cut the traces on the PCB, and solder our wires to their edges; or
  2. Desolder the ICs, and "bypass" them with our new drivers on the external board.
The traces are very thin, ~~0.1mm, with very tight clearances -- about 0.2mm, and they are very short (on the top side). May be these traces are a bit "better" on the bottom side, but to reach them you will have to take apart the 2-layer "sandwitch". Quite undesirable.

The driver ICs' cases have "exposed pads" under them, which are soldered to large copper polygons of the PCB. You will have to bake the whole unit to desolder them.

So, some "dead end" here... My personal skills of "surgical" cutting and soldering will not help anyone else.
 

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Discussion Starter · #9 ·
So, some "dead end" here... My personal skills of "surgical" cutting and soldering will not help anyone else.
:( I was afraid of that. I hear you - it does look really tight.

One thing- do you know if all the lights operate at some PWM output or just the DRL's? The switches don't require PWM; it's just a "feature" to allow dimming.

For example, I can't tell if the reverse lights (I've got LED's) are solid on or a high % PWM.
The drivers for the headlights would probably filter a slow PWM; in fact they sell a module to do just that.

If it's just the DRL's needing the "deceiver" perhaps the project could be a bit simpler for all the other lights because the current feedback is proportional to the actual current. According to the data sheets, the point is to provide a rough range approximation so the BCM's computer can check for loose wires, burned out bulbs, etc.

So, rather than replace the smart switches with ones appropriate for LED's (which would be impossible now), maybe the resistors Rlim & Ris could be adjusted...

I totally agree that faking out these switches and changing the feedback signal is the best way to change from incandescent lights to LED's.
 

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I have a VI Chip BCM - stabilized pulsed DC/DC voltage converter with galvanic separation of input and output circuits. These modules are designed to assemble power supply systems with maximum output power in the smallest possible footprint with up to 93% efficiencies. I installed Vont's LED car lights with control via an app and set up color lighting inside the car. These modules have operating temperatures of -40 to +125 °C and -55 to +125 °C. They are made in ceramic and metal (VIA) housings for better heat dissipation.
 

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Perhaps the problem is in the headlight itself, so it is worth trying to install another. Never buy cheap and low-quality headlights! If the problem is in the system of the car, then it is worth going to the car repair shop. Such a case will cope with a professional! I have never had such a problem because I only buy expensive headlights! Even the lights in a car's cabin, I bought the highest quality: Vont Smart Car Light Strip! LEDs in the car world have become popular due to their energy efficiency and, of course, the brightness of the light. Many LED headlights have better characteristics than expensive xenon adaptive optics.
 

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it has been my direct experience, that the FIAT 500 is not a good platform for conversion to LEDs. The CANBUS style electrical system does not tolerate voltage draws that are not precisely what the system expects. As a result, you will get ghosting and eventually you could fry the BCM. The amount of workarounds that people have tried all seem to point in the direction of futility. Having had to replace a BCM because of LEDs that were "guaranteed" to work, I can tell you that my experience says to quit while you're ahead or don't even start.
 

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I can say right away that you have problems with the electric wiring. The cause is unclear -- there can be many. For example, you purchased low-quality LED headlights. Or you could have made a mistake when installing the LED light. In short, I would suggest contacting specialists. It's good that we live in the Internet era, and they can be quickly found by googling. I had similar problems, but only with a led strip light, and as it turned out, I installed it incorrectly.
 
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