First point is to fix the two front side marker lights, left and right.
Wear and tear has cracked the glass and time has rusted all internal parts on both ligths.
Bought two universal kits from biltema, they did not include instructions.
There was nothing to salvage in the old light bodies.
At least there was som spare wire ti cut and strip-
Contents of the box, not too difficult to assemble
Crimped two small ground wires. One should not solder connections for outdoor usage.

Adapters, fot left and right side.

Internal view, excess wire coiled.
Bench supply was used to test the installation.
Right side ok.
Left side ok.
Lights are all ok, next item is a completeely new bed.
Sad state of trailer bed, it has been rotting under snow and leafs for some years.
Hopefully frame has survived
After removing some carriage bolts and the D rings every poece of
the rotted bed could be removed.
The chassi is in excellent shape.
After spending som time researching what options I had for what
bed could be suitable as replacement, I settled on 120x28 decking
boards, impregneted and the fasteners to be hidden
Perfectly packed side to side can not be done, recommended gap
is 124mm to 127mm
for 120mm boards.

Tight stacking is not recommended.
All boards need to be cut to size to fit, cant do it afterwards.
Front of trailer has a recess where a notch is necessary.
all spacing was done before add fasteners.
fot the sides longer carriage bords was ordered since the bed has increased in thickness from 16mm to 28mm.
From underneath screws are drilled at an angle of approx 30°
through cut pieces of 120x28 that held down the ved with help of
the chassis frame. approximate spacing of 40cm.
The rear of the bed di not have much margin for error whan adding
carriage bolts.
3D printed a jig tha could be centered on the exit hole in the frame and then guide the drill.
It was a noticeble increse of weight when all was installed.
not unexpected since the impregnated wood is new, time will dry the boards
and it will lose a lot of wet weight.
The repairs worked wonders, it has now been through MoT (Sweden)