Led's headlight issue

[Tha fios agaibh]

I thought i had to solder a resistor . Would it get hot?

I'd recommend mechanically crimping or screwing your connections over solder alone. A 25 watt resistor shouldn't get too hot, but I'd use shrink tube as opposed to electrical tape on its leads. You might want to use a resistor that can be mounted to the car frame or fender where it Will act as a heat sink.

 

[Nehmo]

What kind of error light are you talking about? It seems it can't be the check engine light as that isn't related to the lamp circuit. But I don't know everything. Maybe on your car it is.
If it is just a lamp circuit indicator of low current, then why not just live with it? (Or disconnect it.) Jumping across the LEDs with some resistor defeats one of the advantages of LEDs.

 

[hevans1944]

What kind of error light are you talking about? It seems it can't be the check engine light as that isn't related to the lamp circuit. But I don't know everything. Maybe on your car it is.
If it is just a lamp circuit indicator of low current, then why not just live with it? (Or disconnect it.) Jumping across the LEDs with some resistor defeats one of the advantages of LEDs.

Back in the day, my wife and I would do a walk-around inspection every month or so while one of us operated the controls inside the car: brake lights, tail lights, turn signal lights (front and rear), parking lights, courtesy lights, dome light, interior light(s), and head lights (upper and lower beams). It was fairly easy to tell, even in bright daylight, whether a light was burned out or not. I guess the current generation can't be bothered to do a walk-around, so needs a dashboard indication to inform when a light doesn't operate.

@Nehmo, you can't disconnect anything on a modern automobile without the computer knowing about it and nagging you to put it back. And you can't disconnect the computer (which is distributed throughout the automobile) either, for then the car won't run. It won't even start. Maybe when the world runs out of fossil fuel everyone will switch to pedal power.

 

[Nehmo]

@Nehmo, you can't disconnect anything on a modern automobile without the computer knowing about it and nagging you to put it back. And you can't disconnect the computer (which is distributed throughout the automobile) either, for then the car won't run. It won't even start. ...

If it's just an indicator lamp, I doubt the computer would notice. But I don't know. My car, of 2001, doesn't have a lamp out indicator. However, on my older car, if a trun signal incandescent opens, the driver will be alerted by a fast blink rate of the turn signal indicator on the instrument panel. Replacing the turn signal bulb with an LED will cause the same fast blink but it can be remedied by a special flasher unit for the purpose.
OP's, "bring up the warning lights on the car error system" may or may not be an indicator light. It could be a OBD-II code that he's talking about. That's why I asked.
OP probably has the above mentioned lamp out indicator. He would have to remove the instrument cluster to get to it. A simple way would be to cover it with a sticker or something, perhaps a little happy face. A translucent one would have the advantage of being illuminated from behind!

 

[portishead]

Back in the day, my wife and I would do a walk-around inspection every month or so while one of us operated the controls inside the car: brake lights, tail lights, turn signal lights (front and rear), parking lights, courtesy lights, dome light, interior light(s), and head lights (upper and lower beams). It was fairly easy to tell, even in bright daylight, whether a light was burned out or not. I guess the current generation can't be bothered to do a walk-around, so needs a dashboard indication to inform when a light doesn't operate.

@Nehmo, you can't disconnect anything on a modern automobile without the computer knowing about it and nagging you to put it back. And you can't disconnect the computer (which is distributed throughout the automobile) either, for then the car won't run. It won't even start. Maybe when the world runs out of fossil fuel everyone will switch to pedal power.

So to clarify gentlemen - it's a BMW f30 daytime running light bulb challenge!! ..... I have changed a normal bulb to an led. Clearly it's much lighter on the power it consumes. The computer decides that the bulb has blown and shows on the dash - DAYTIME RUNNING LIGHT FAULT. CHECK FAILURE. It also bongs every time you start or stop or get out the car. It's a pita.
So, I just wondered if I could fool the car somehow. Obviously not that easy.

But here's the point...

https://www.google.co.uk/search?q=f30+drl&client=ms-android-sonymobile&prmd=isvn&source=lnms&tbm=isch&sa=X&ved=0ahUKEwign6PS-dXOAhWLAMAKHYtSCYMQ_AUIBygB&biw=360&bih=512#imgrc=RmOaiammBCZwaM:

 

[Herschel Peeler]

Hi all,
I dont know if this is the right place... But I am after a little help. I have swapped out my daytime running halogen bulbs in my car for a couple of led bulbs. These bulbs (only £10) Nothing expensive say they are canbus error free however, the bulbs work nicely but bring up the warning lights on the car error system. I guess the leds are less power and the car thinks the bulbs have blown?? Does anyone know a work around for them or what I could use to correct it???

These are the bulbs if its of any help....

Thanks all

http://www.ebay.co.uk/itm/252415530198?_trksid=p2057872.m2749.l2649&ssPageName=STRK:MEBIDX:IT

Can you contact the manufacturer of the LED? This isn't likely a new problem to them.

 

[Herschel Peeler]

Hi all,
I dont know if this is the right place... But I am after a little help. I have swapped out my daytime running halogen bulbs in my car for a couple of led bulbs. These bulbs (only £10) Nothing expensive say they are canbus error free however, the bulbs work nicely but bring up the warning lights on the car error system. I guess the leds are less power and the car thinks the bulbs have blown?? Does anyone know a work around for them or what I could use to correct it???

These are the bulbs if its of any help....

Thanks all

http://www.ebay.co.uk/itm/252415530198?_trksid=p2057872.m2749.l2649&ssPageName=STRK:MEBIDX:IT

I found a video on youtube of a guy replacing the bulbs and that's all he did. No problem mentioned.

 

[portishead]

I found a video on youtube of a guy replacing the bulbs and that's all he did. No problem mentioned.

I expect these are just cheap from China.

The car just thinks the bulbs are blown. I though there might be an easy way to modify the bulb. I guess not. Probably faulty

 

[Tha fios agaibh]

So, Have you tried or ruled out the resistor idea?

 

[dave9]

Although this is an old topic, the solution that I consider the best was not mentioned and others may happen upon this topic with the same issue, more and more often since more and more vehicles now have bulb out indication.

These bulb sensing circuits typically feed the power through low ohm resistors and sense the voltage drop across them and output a signal to the computer that there is a fault if that drop is too low.

Trace the circuit to that current sensing module. It will have thick traces to handle bulb current, and (expectedly) thin ones for the sensing. Cut the thin sensing lines and it cannot signal a bulb fault. If you later wish to put the stock incan bulbs back in, solder a jumper wire point to point between the two points on the PCB that the cut trace was connecting.

The other option is to reverse engineer the circuit more and substitute different resistor values such that the measured voltage drop is within specifications. This requires the datasheet for the comparitor chip and some equations typically also provided in the datasheet.

The last alternative is to modify the wiring itself, to simply jumper out the module, connect all bulb leads directly to the power source incoming into the module, instead of through the module and disconnect the module so it cannot signal a bulb outage.

 

[Tha fios agaibh]

These bulb sensing circuits typically feed the power through low ohm resistors and sense the voltage drop...
Trace the circuit to that current sensing module. ....Cut the thin sensing lines and it cannot signal a bulb fault. .....
The last alternative is to modify the wiring itself, to simply jumper out the module, connect all bulb leads directly to the power source incoming into the module, instead of through the module and disconnect the module so it cannot signal a bulb outage.

Problem is, the control module for the headlights on most cars do the current sensing and are usually inaccessible because they are potted and the sensing circuitry would be tiny.

Secondly, if you just cut the sensing trace it would read it as open circuit and give spurious feedback from floating.

Yes, the resistor value could be calculated and changed but most would agree impractical.

Third, most canbus systems will send a fault if it doesn't communication with all modules, so it's unlikely you can simply disconnect the module.

 

[dave9]

Problem is, the control module for the headlights on most cars do the current sensing and are usually inaccessible because they are potted and the sensing circuitry would be tiny.

Secondly, if you just cut the sensing trace it would read it as open circuit and give spurious feedback from floating.

Yes, the resistor value could be calculated and changed but most would agree impractical.

Third, most canbus systems will send a fault if it doesn't communication with all modules, so it's unlikely you can simply disconnect the module.

No the sensing circuitry cannot be tiny. It has to have large low ohm resistors so it doesn't overheat, and thick traces to carry the bulb current.

While I cannot speak for who does pot theirs, I have never seen any that are potted.

I did not mean to suggest cutting the sensing trace where the bulb current is flowing. You cut the trace going from the comparitor to the computer. This does not "give spurious feedback", whatever that is supposed to mean. There is no floating issue, it is either a low (0 in this case) or high signal to indicate bulb out. Cut it and you have 0.

I am not claiming every vehicle make and model uses the exact same scheme, but it is a starting point and only rational to tackle the problem where the problem is, that the module itself is not behaving appropriately for bulbs that use less current.

How is it impractical to calculate and replace resistors? Many of us have quite a few standard value resistors lying around, otherwise it is a few cents cost component. This would take me significantly less time and expense than going around finding, ordering, receiving, then soldering special load/ballast resistors onto every bulb run... some of which will need housing removed just to gain access, and also need heatsinking to last long term so there's mounting them too, if there is room to do that or else you're making a second wire run just to remotely mount the load resistor.

All in all, cutting the feedback traces can take less than 10 minutes. It is by far the quickest, cheapest (free), and least intrusive way to get the job done. And reversible with a few scraps of jumper wire.