Technical Ducato X250 2007 motorhome rear side light problem

[gm6vxb]

Have a problem with (now) both rear side lights not working on a 2007 X250 Lunar motorhome.
Initially I thought it was just the near side high level marker bulb blown, but then found the rear sidelight also not working.
Unfortunately I did try the bulbs on the offside and now have problems with both sides.
Bulbs, and connections all appear ok and have tried new bulbs but not buzzed back to the fuse box area yet due to rain stopping me, but suspect wiring and connetors are ok.
If I check volts with the bulb removed (either side) I see a good 12.5 volt, but when I put the bulb back in, it lights for a second and then it goes out and volts drop to Zero (this on both sides)
I know the side lights work through 'resetable' fuses so this is obviously tripping probably with over current ?. Bulbs out and power off and back on and seeing volts on the connector again.

Hate the thought of calling in a mobile techician to check as not many 'good ones' up here in North East Scotland.

I am struggling to find either a good description or circuit diagram for the 2007 Ducato which is not helping me fault find.
Can anyone point me in the right direction ?. Got good Volt/Amp meters and oscilloscope here for checks.

Thanks,
Martin, GM6VXB

 

[rayc]

any help?

 

[Reg 65]

If you fit new bulbs they need to be the same wattage as the originals, otherwise the body computer may think its a fault and turn them off.

 

[gm6vxb]

Rayc,
Yes, been working with the diagram as it is then only one I have found so far that is useful. Unfortunately it looks like a copy so some of the
numbering is difficult to read but think I have enough to do more checks tomorrow.
Indicators and brake lights work as normal and use the same earth connection so ruled earthing problems out.
Tomorrow if it is not raining will go through all the connectors and double check all lamps are the correct wattage again.

 

[rayc]

Rayc,
Yes, been working with the diagram as it is then only one I have found so far that is useful. Unfortunately it looks like a copy so some of the
numbering is difficult to read

lt is taken from a cheap DVD workshop manual sourced on ebay for about £5. Unfortunately when you print off to a pdf it is a bit blurred. If you want any particular bit in clearer detail let me know

 

[gm6vxb]

Happy to say FIXED this morning before the rain starts again !.

Fault was a 10 Watt festoon lamp rather than a 5 Watt one fitted in the high level rear marker light.
Must have accidentaly put the wrong one in while doing checks.
At least I now have a better understanding of the electrics to the rear of my motorhome.

 

[Reg 65]

Thanks for letting us know - some people don't bother
Thought thats what it would be as the symptoms you describe are exactly what happened when I put a bigger bulb in
' lights for a second and then it goes out and volts drop to Zero '
Computer says No