LED headlights got the pro's puzzled

[Dav-Tec]

Hi guys and gals.

I'm after some help. Before we start any help given that directly results in the rectification of the won't go unrewarded. I have found some forum's (not this one to date) to be against helping businesses as we earn money from fixing these things. Anyway I digress.

So if you could read through the following post. The vehicle came to me after already having known working lights removed from one vehicle and fitted to this one. This vehicle has LED lights from factory. We tried various things including recoding and Re-Parameterizing the BCM using ODIS which initially appeared to fix it. However a few hours after it leaving the workshop the issue reared it ugly head and we where back to square one. After consulting some wiring diagrams and a few others in the trade I came to the conclusion it must be the BCM as the lights have been replaced. However after changing the BCM and coding it using ODIS this appears to not be the case.

The fault happens in Auto and manual modes on the light switch. There doesn't appear to be a set pattern. It's now driving me, the vehicle dealer and his customer nuts.

ALL HELP WILL BE GREATFULLY RECIEVED!

Many thanks
Chris

Thread 'Blinking/flashing factory LED dipped beam' Blinking/flashing factory LED dipped beam

 

[Dellmassive]

fwiw . . .

my initial though looking at the first post was power issues.

either volt drop under load, or poor ground connection.

high resistance.

causing the voltage drop error to be flagged.

+++++++++++

i would retest with fat test/jumper/temporary leads to give the lamp module a good known power and ground feed.

ovbs the LED lamps have there own ECU thats CAN/LIN controlled. so they can flag there own error codes.

but I'm thinking issues with power and / or ground supply.


can you meter or scope out the power feeds with a logger and go for a drive,

as its intermittent it may be heat or vibration related.

maybe get a voltage logger connected and go for a drive while monitoring the feeds.?



++++++++++++

 

[Pauly]

If we colab the data from there and here the headlights and power modules have been swapped with known good ones and still faulted and the bcm has been swapped and still faulted so if we rule out those items that only leaves the wiring and the voltage passing through it

I assume the new BCM had the coding rebuilt from ODIS ? this would put it back to factory and rule out any interference before he bought it

Has the battery been tested ? think i would get the battery properly load tested or if its the original i would just swap it for a new one as its coming to the end of its life anyway

After that where do you go ? maybe unpin the connectors to check for corrosion and measure the impedance of each cable from headlight plug back to bcm/levelling module etc to check for any high resistance joints or issues, and/or start measuring voltages at various pins although you will prob need a scope to measure a couple of them accurately and get any meaningful data

The only thing at the back of my mind that doesnt add up is the fact it happens to both sides and gives several error codes, if you had a high resistance joint or a loose or corroded line you would only expect one issue ........

 

[Dav-Tec]

fwiw . . .

my initial though looking at the first post was power issues.

either volt drop under load, or poor ground connection.

high resistance.

causing the voltage drop error to be flagged.

+++++++++++

i would retest with fat test/jumper/temporary leads to give the lamp module a good known power and ground feed.

ovbs the LED lamps have there own ECU thats CAN/LIN controlled. so they can flag there own error codes.

but I'm thinking issues with power and / or ground supply.


can you meter or scope out the power feeds with a logger and go for a drive,

as its intermittent it may be heat or vibration related.

maybe get a voltage logger connected and go for a drive while monitoring the feeds.?

Hi mate, I did check connections and all seems ok. I'm happy to recheck. I had a power supply to the van the other day and it did it then, with and with the engine off, bonnet open or closed all the time the vehicle was obviously stationary. Looks like I'm buying an oscilloscope. Usually don't get this involved in diagnostics but now I'm this far in I want to know what the hell it is!

 

[Dav-Tec]

If we colab the data from there and here the headlights and power modules have been swapped with known good ones and still faulted and the bcm has been swapped and still faulted so if we rule out those items that only leaves the wiring and the voltage passing through it

I assume the new BCM had the coding rebuilt from ODIS ? this would put it back to factory and rule out any interference before he bought it

Has the battery been tested ? think i would get the battery properly load tested or if its the original i would just swap it for a new one as its coming to the end of its life anyway

After that where do you go ? maybe unpin the connectors to check for corrosion and measure the impedance of each cable from headlight plug back to bcm/levelling module etc to check for any high resistance joints or issues, and/or start measuring voltages at various pins although you will prob need a scope to measure a couple of them accurately and get any meaningful data

The only thing at the back of my mind that doesnt add up is the fact it happens to both sides and gives several error codes, if you had a high resistance joint or a loose or corroded line you would only expect one issue ........

Exactly! It make no sense. It can be fine for several hours then go off for a split second and the be ok for several minute then do it twice or 3 times every so many minutes or not at all. Mira Hinsley is more stable than these lights!

 

[Dav-Tec]

So trying to work out which way to go regarding kit for finding this fault I'm looking at everything from £200 scopes to a Snap-On Modis Edge diagnostics tool with built in 2 channel scope lol.

Any ideas what readings I should be getting and at which pins anything to look out for from people's previous experience.

Just a quick thought could it be the range controller?

I'm with you @Pauly I don't understand why it effects both as they both have there own wiring. Btw to be clear both bcm units where Re-Parameterized and coded using ODIS to eliminate any coding issues. Only tried a bcm after that incase it was a relay or something inside failing.

Cheers
Chris

 

[t0mb0]

Random (unlikely) thought, but given that the issue is so weird with it affecting both lights on independent wiring with replaced lights and bcm, might be worth a thought. There’s not any really non-standard wireless/radio kit on board is there? Just wondering whether anything could interfere with something in the LED units themselves?

Other than that, is there any commonality at all in the wiring circuits for each? What about the earth, any chance of a common earth fault?

And the simple one - you haven’t got a dodgy headlight switch/wiring have you? And if the headlights are auto, check the daylight sensor and wiring for that.

 

[t0mb0]

I hadn’t noticed the low voltage warnings. In that case, I’d definitely trace both the power and earth back to the first point common to both lights (which might be the battery itself for all I know) and check/log that.

 

[Pauly]

Random thought, if the van has tailgate then theres cables to pins 28 and 56 but if you have barn doors then they are doubled up on one pin (as the other deals with deadlock on rear door)

Not sure what voltages to expect on a scope, i seem to remember @Robert put one on some of his cabling and did post it somewhere but would need to have a search to find it, think theres a few more basics to go through before you get to that point though ?

 

[Robert]

...

And by the way, all of the wiring from the halogen setup(either H4 or twin H7) can be reused for the LED lights except for the side lights.
Two new wires have to be run from BCM plug B
PIN5 to LHS lamp PIN10
PIN6 to RHS lamp PIN10
The reason is below.

View attachment 19044

This is the voltage produced by BCM to the LED headlamps on PIN10 when side lights are switched ON.
At the same time 12V DC is supplied to PIN12.

And when DRLs are switched ON both PIN10 & PIN12 receive 12V DC.

If there is only one PIN(either 10 or 12) supplied with 12V DC DRLs/sides will remain OFF. Obviously this should not happen when retrofit was carried out properly.

Both low & high beam are 12V DC.
And when engine is running voltages are as follows.
View attachment 31755
View attachment 31756
Low beam is actually produced from the module with 3 LED chips and high beam module consists only 2 LED chips.
And this is the reason why the current consuption is lower on high beam and cable size was reduced accordingly.

In general LEDs are way more efficient than halogen light bulbs and therefore produce much more light with less wattage.

My DRLs with engine running.

Voltage at PIN 12.
View attachment 31855
And voltage at PIN 10
View attachment 31856

By the way, have you done any coding yet?

 

[Dav-Tec]

Could it be the light switch? A forum member contacted me asking this and to be honest I had the same question myself

 

[Texxaco]

It seems the light switch is the only thing left to check, can you access a working one rather than purchasing one?

 

[Dav-Tec]

No lol. Nothing in stock

 

[Howzat]

Maybe you could bridge the pins on the plug?

 

[Dellmassive]

I'm still going powers and grounds.

I have a snapon verus pro that has a scope.

I also have a Mobile Hantek scope.

The way I would test... Is to back probe the main power at the light plug... And a good chassis ground.

Then set the scope to a long time base so it I'll record about 60sec for one screen.... Start recording then go for a drive.

Or watch the screen while someone else drives.

Look for any iffy drop outs or low volts. On the 12v rail.

You can scope out the main neg to.... That should be near. Chassis 0v. So any hash on the screen could indicate bad ground.

.......

But simplest test would be to just add in jumper wires for a known good power and ground.

....

 

[Dav-Tec]

I'm still going powers and grounds.

I have a snapon verus pro that has a scope.

I also have a Mobile Hantek scope.

The way I would test... Is to back probe the main power at the light plug... And a good chassis ground.

Then set the scope to a long time base so it I'll record about 60sec for one screen.... Start recording then go for a drive.

Or watch the screen while someone else drives.

Look for any iffy drop outs or low volts. On the 12v rail.

You can scope out the main neg to.... That should be near. Chassis 0v. So any hash on the screen could indicate bad ground.

.......

But simplest test would be to just add in jumper wires for a known good power and ground.

....

Would we need to take it a drive? It does the fault when stationary?

On a side note what do you think to the snap on Versus?

 

[Dellmassive]

Verus.. very expensive, overpriced.

They want £100 a month for updates. (Tied into a 12mnth contact)

The scanner side of it is ok for most EU motors iv had it connected to.

The scope side is good... That's what I use it for most.

.....

TBH I wouldn't bother with it again I had to buy again.


....

I have the Autel Maxidas scanner... That's much cheaper to buy and update.

Had it for about 5years. Updated it last year

....

Bth no scanner is as good a manufacturer specific laptop software and adapter.

.....
So I'd say get a basic scanner for code reading etc. Autel are good.

Get the laptop software for make, IE vcds, Odis,. Vaux , BMW, ford. Blah blah.

Then get either a PC scope box for your lappy..... Picoscope is the norm, or get a cheaper cloan, like a Hantek box.


Or get a battery powered portable scope meter.


.

As long as you can slow it down enough to do scope meter..... Recording/logging .

And speed it up fast enough to read/see CAN data..... It will be fine.

2x channels should be enough.

....


The most common tools I use it a multimeter and current clamp..... And those are the cheapest tech tools in the box.

 

[Dav-Tec]

Ok so I have the van for a few days but I have limited time with it as I'm juggling my other job and preparing for yet another knee op.

Initially though it was a bad earth at the earth point in the engine bay near the drivers fog light, cleaned it up better resistance readings but still not great so wired in a new wire from the drivers headlight pin 7 to the chassis earth point mentioned above reduced the resistance from 38 Ohms to 7 Ohms so quite an improvement. Nothing happened all days with the lights on for what probably equated to around 5+ hours nothing several times that night when I checked on it for 10 mins at a time every hours or so again nothing.

Then last night doing a remote headunit unlock for a forum member, lights had been on for approx 40 mins and then the light(s) (not sure which one as it was out the corner of my eye) blinked. Started to check various wires see photos attached.

I've connect up my fancy multimeter set it to record the voltage of pin 6 at the back of the drivers headlight for the next hour as that looks to be the correct wire for powering the dipped beam. Upon setting this up the bloody passenger side blinked but no trigger on the logging of the multimeter so either only that one did it or it's not that terminal that's doing it (as in terminal 56).

I've also recorded a snippet of the PWM at the light but not sure if it's correct been a while since I got this in depth as I usually steer clear of things this far in as I'm not really set up as a general auto electrician.

Anywho any input would be grand as this one is bugging the hell out of me!

Thanks everyone

 

[Alster]

I don’t know much about car electric’s but in my world ( domestic appliance repair) 7 ohm would be considered a bad earth- the earth bond on a washing machine should be better than 0.1 ohm. Don’t know whether this is relevant or not…Alan

 

[Dav-Tec]

I get 0.25 with the ignition off it the. Rises when the ignition is turned off. I still think it's a ground issue but Christ knows where. I did connect the oscilloscope to a bolt on the wing and one of the grounds I. The driver's side light plug and picked up some form of noise.