General unusual flasher problem

[brianfixit]

I have a 14 plate ducato 130 motorhome and the problem I have is with the n/s flashers ,on selecting this side the indicators flash as they should but after about ten beats they start to flash quickly as if there is a bulb out but the problem is that all three bulbs are working as they should its only inside that's flashing quickly and dash saying check n/s bulbs, just changed front and mirror bulbs but can't change rear as its fancy LED strip type. checked the handbook and strangely doesn't list a relay for the indicators. as I stated everything is working ok its only the dash and the warning that's amiss. Would be grateful for any suggestions to the cause and rectifications of my problem.
Brianfixit

 

[rayc]

The bulb failure circuitry and indicator drive circuits are part of the body computer. It appears that the bulb failure circuitry is sensing an incorrect current draw therefore suspecting a bulb failure.
I think you can ignore the mirror indicator bulb as when my mirror was damaged, including the bulb, no fault was reported by the bulb failure circuit.
It could be that the led strip is not giving the correct current draw as it heats up, i.e its load resistor is faulty?

On my MH it would be relatively simple to swap the LED strips from one side to the other to see if the fault changes side.

 

[brianfixit]

thank you for your reply so I have now changed rear LED lights from one side to the other but the problem remains the same and now at a complete loss as to what to try now. Anybody got any ideas for what I should do next.
Thanks

 

[whine0]

What make of camper is it?

 

[brianfixit]

chausson 718 eb welcome 2014 registed

 

[whine0]

If you got full led lights on the back they are controlled by a ecu in the back cupboard or locker you should hear it clicking with indicator on ,its most probably a Sargent vlm5 and it’s faulty

 

[rayc]

Chaussons are built in France and I very much doubt any Sargent equipment is fitted to it. My French built Pilote has full rear led strips and I can assure you there is no Sargent systems in it. The Proplast led strips are fed directly from the rear harness connector on the chassis near the rear axle with no interfaces in between.

http://www.proplast-online.de/en/Pr...-LED-Direction-Indicator-Lamp-PRO-CAN-XL.html

 

[whine0]

Apologies may be la Sargent then! Is worth splicing a 21w bulb in circuit see how it behaves only other thing known this issue on ducato is software on body computer

 

[brianfixit]

as I stated in my original post all the indicators are working as they should but its just in the cab that its coming up with the message check nearside bulbs and flashing fast as if there is a bulb duff. I am suspicious that it might be the printed circuit board behind the dash as i know they can give some weird problems,they can be sent away to a company near Portsmouth and repaired for £150 but am reluctant to go down that route until I have some more info from someone who could give me more about if it could be this PCB
The circuit board is easily removed with just four screws.

 

[rayc]

The PCB behind the dash, well also behind the fuses, is the body computer. I believe it is possible to interrogate it via the OBD port to ascertain any reported faults. Before I removed it I would want to know for sure that there is nothing wrong in the wiring or lamp cluster/holders. In any event whine0 said that it could be a software issue on the body computer.
By the way the lamps may be operating correctly but it only takes a small variation in current for the body computer bulb fail circuit to indicate a fault. The fact that it does not do so until 10 or more flashes appears to indicate it may be heat related due to a poor joint/bulb holder/ rear indicator lamp LED ballast circuit/front indicator bulb etc.
On my MH the rear lamps connect into a multi block connector on the nearside chassis member just rear of the axle. Can you check that there are no obvious problems with this connector? I wonder if the diagnostic tool can switch each side on permanently rather than trying to fathom things out whilst it is flashing?

On a 2008 Chausson Welcome 75 I had I was getting a offside rear side light failure indicated. The lamp appeared to be working correctly. On inspection I found the combined side/brake light bulb was slightly misaligned into the bulb holder. I removed it and reinserted it and it worked with no fault afterwards.

 

[brianfixit]

This morning I went under the van and cleaned the multi pin connecter with electrical cleaner as suggested plus another one right at the back near the bumper but fault is just the same n/s flashing normal for about 8 beats then going fast and dash saying check bulbs, front bulb and mirror bulb changed and rear LED one changed from other side, definitely agree got to be something heating up somewhere. certainly got me scratching my head and don't want to have to put it into Fiat unless I have to.

 

[rayc]

You have my sympathies and of course the fault could be the body computer itself. I suppose you could try fitting a bulb rather than the LED unit as suggested by whine0

 

[brianfixit]

But there doesn't seem anything wrong with the LED rear as it works ok on the other side in
No

 

[whine0]

You only need to fit a 21w bulb to see if it still does fault
Only temp job this might prove if a software problem because a standard van would use bulbs have you diag tool that can read software version body comp can multiecuscan read body comp software version ? Any body out there??

 

[RS3100]

Yes MES will show body comp sw version. It can also activate lamps through body comp and plot/measure circuit voltage etc during operation.
Don't know if I might be barking up the wrong tree, but fast flashing can be a symptom of can controlled bulb circuits fitted with an LED lamp if resistance is incorrect or resistor faulty. Don't know whether the LED lamps in this case have the resistance built in, or if they rely on an additional module somewhere in the loom. If its a coach built MH, only the wiring in the cab will be original Fiat I believe. The wiring from there back to the rear lights will have been added by the MH converter.

 

[RS3100]

Also OP when you mention ECU that can go faultyxand be repaired for about £150, that is the instrument cluster. Common fault is spurious warning lamps in the instrument panel illuminating faintly for no reason. It is not your problem.

 

[brianfixit]

the saga continues,today I disconnected the LEd light and connected a bulb holder with a 21 watt ordinary bulb and the problem was no longer there but this of course is not really the answer, I then I decided to link both the LED light and 21 watt bulb together and once again everything is working ok. I then tried linking together the mirror bulb and the 21watt bulb and this worked ok but the trouble is to do this as a fix I need to have a smaller 21 watt bulb and holder to fit along side the normal bulb as there is little space to get it in ,is there such a thing as a small 21 bulb and holder. This is not an ideal fix but if it works so be it ! Many thanks to all who helped with advice etc.
brianfixit

 

[irc]

Possibly the LED unit is fitted with a resistor and it has failed. This could make the CANBUS system think a bulb has blown.
Re-soldering or splicing in a suitable replacement could fix it cheaply...

 

[whine0]

Get some 6.8ohms resisters off eBay and fit them them instead of bulbs there alot smaller than bulb and holders

 

[rayc]

the saga continues,today I disconnected the LEd light and connected a bulb holder with a 21 watt ordinary bulb and the problem was no longer there

Perhaps there is a seperate LED ballast resistor that was not part of the bits you swopped over from side to side when the fault did not change sides? Anyway you have had good advise in to fit a new resistor that simulates a bulb [21w@12v = 6.8R] . There are 4 in this kit for less than £6
https://www.ebay.co.uk/itm/4X-LED-I...230209&hash=item25efb4b5ac:g:uXoAAOSw4qxaoPuA