General Side marker lights

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General Side marker lights

daverally

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Hi,

I have a failure code and I don't understand what is the exact problem.
The MultiECUscan say the side marker litghts are not works properly on both side. This is Maxi version, so as I know in this car originaly there are 3 lights/ side.
One of them is coming from under the cabin step
and rest 2 are coming from end of the car (from the wiring harness).

What is this connecting method are OK?
The fuse has been replaced and all lights are working.
Where should I check the source of the problem?

Thanks a lot.
 

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You have not given any vehicle details, as requested at the top of the Ducato page.

Therfore I can only assume that the vehicle is relatively new?

Are three side marker lights standard equipment, or part of a conversion?

Just a guess, but is it possible that the Body Computer Module (BCM), is seeing a current flow to the marker lights, which is outside programmed limits, either too high, or perhaps too low if LED lights are fitted?
 
Hi,

Sorry, I forget to mention.
The car is: 2011, Fiat Ducato Maxi 2.3 Multijet 120

When I bought this car, the previous owner placed 3 lights on both side. I don't know that orginally how many light is on the Maxi version. Do you know it?

All of them are LED. BUT I checked it can communicate with the computer.
The licence plate light is also LED, and when I replaced it, the failure code deleted from the car automatically.
Do you know can I check the current flow via MUltiECUscan?

Thanks a lot :)
 
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When a cab is supplied to a motorhome manufacturer there is a 'lights on signal' - normally a battery negative when lights are on, left by Fiat to be used for the side marker lamps. The lights on signal usually operates a relay in the motorhome manufactures electrics which powers the side markers. The marker lamps are therefore buffered from the Fiat BCM and do not effect the lamp failure circuits.
I suspect the previous owner connected the side markers into the side light circuits so that they work but in doing so trigger a lamp failure in the BCM because to much current is seen to be drawn.
 
When a cab is supplied to a motorhome manufacturer there is a 'lights on signal' - normally a battery negative when lights are on, left by Fiat to be used for the side marker lamps. The lights on signal usually operates a relay in the motorhome manufactures electrics which powers the side markers. The marker lamps are therefore buffered from the Fiat BCM and do not effect the lamp failure circuits.
I suspect the previous owner connected the side markers into the side light circuits so that they work but in doing so trigger a lamp failure in the BCM because to much current is seen to be drawn.

Having reread the previous post from the OP it would appear I was not correct in thinking they had been added to a side light circuit etc. Perhaps the LED ones are not original and replaced bulb lamps?
 
HI,

It's not the original lamp, but i tried to connect 5W lamps to this wiring round, the problem is same :( I have no idea, what needs to be checked or what is the issue.
 
This may suggest that the displayed fault is not an actual one? You would expect the fault condition to change when the lamps were disconnected??
 
The previous owner did some changes and when I bought the failure come was available in the system. I wanted to fix it, bit it seems to not to easy.

Yes, the car is long vehicle, it's Maxi version.
Only the orange lamp is lighting on the board.
If its ground issue, where should I check ?

I disconnected the lamps and failure code is same.
The front light is working on both side, but I try to disassemble the light and change bulbs.
 

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Hi,
This issue still not solved. Does somebody have any what is the problem?
Thanks a lot.
 
When a cab is supplied to a motorhome manufacturer there is a 'lights on signal' - normally a battery negative when lights are on, left by Fiat to be used for the side marker lamps. The lights on signal usually operates a relay in the motorhome manufactures electrics which powers the side markers. The marker lamps are therefore buffered from the Fiat BCM and do not effect the lamp failure circuits.
I suspect the previous owner connected the side markers into the side light circuits so that they work but in doing so trigger a lamp failure in the BCM because to much current is seen to be drawn.
Given that this is the method of switching the marker lights for a motorhome, it is worthwhile checking for the presence/functioning of such a circuit on the OP's vehicle. (If built on a chassis cab it may well use the same method, and whoever converted the unit could have led the wiring anywhere).

As Ray says, if a "converters socket" is fitted, there is a signal on a connector there which drops to ground when the side lights are on. This signal is used to switch a relay, through which the marker lights (permanently connected to +ve) are powered. If there is a problem on the relay circuit (or the relay has been by-passed causing high current draw at the BCM), it might well throw a code.

The manual downloadable from the forum here:


details the methodology for later vehicles, but I suspect it has been the same/similar since the X250 and Canbus were introduced.

Pages 3.14 3.15 and 3.19 are the most relevant.
 
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