Side Light Marker Woes 😔

[7Hvn]

Side Light Marker Woes
Had the motorhome booked in for its MOT on Wednesday. On my checks before heading to the garage I found out that the NS rear upper marker and NS rearmost side marker are out! Swear words! Managed to delay MOT for a month.
Been debugging today and found a length of cable just before the rear side marker that was lacking continuity.
In the process somehow I’ve now lost all NS side markers. OS markers all present and correct. No warnings on the dash.
After a bit of research it turns out that as it’s a coach built it doesn’t have a fused system for the side lights each side. They are apparently controlled by the CAN-BUS system. Reading online it says to disconnect vehicle battery for min 30 mins to clear CAN-BUS control unit memories. I’ve done this and left it an hour. Still nothing!
Also tried disconnecting Hab battery and solar at the same time. Still nothing! Grrr
In the meantime we have replaced the erroneous cable but still nothing.

Going to leave the hab battery disconnected for longer but I’m clutching at straws!

Anyone any ideas? Thanks in Advance!

Vehicle Details:
Fiat Ducato X250 2010 3.0ltr 160bhp
Dethleffs Advantage A7871-2 SG

 

[Revolvor]

I may be wrong, but I don't think the high-level markers are tested during the MOT. My MH passed with a front high-level marker not working. Also, on my Autotrail , the marker lights are NOT controlled by CAN-BUS. They are part of the converter electrical system, controlled by the EM50

 

[sgl5gjr]

My marker lights on the side and upper rear were wishy washy....the upper ones had corrosion in the holders....took the covers off....brass wire brush on my dremel to clean up... bit of vaseline and some warm white led bulbs....perfect.... side markers were also pretty poor on corrosion...so I popped new LED units on... Thing with motorhomes they sit around too much...and with makers not exactly keen on spending a few extra pence to stop the corrosion happening...then we are always going to be up against it...... have fun out there.....

 

[KUSKUS]

I changed a bulb on a Burstner motorhome and all the side markers went out.
Searched every where for a fuse but as you said canbus controls it.
Looked at the bulb and it was the wrong amperage, fitted the correct one then all ok