No brakelights behind, both dark

I can find out of this my self, but then I probably need an electronic scheme.
the story- this if most certainly the only voyager with a manual gearbox so called trans-axle, in Norway maybe in the whole Europe.
The automatics break down after a rather short mileage, but my brake lights behind disappeared after the conversion to manual(works fantastic). BUT the brakes light behind disappeared on both lamps.
I know that it is probably some wire under the dash that must have been cut of or grounded, because the fuse in 20 amp is blown, but I can not find which one, but there is a huge bundle up under there, so I hope you could help me with how the electrical wires are connected and how they and where they are lead to the back of the car