Jetta A3 95 Velocimeter Electric Fault, Lights

Hello, how do I need your help. I have an A3 1995 Motor 1.8, but recently I present a problem, the tacometer and the speedometer stopped working, sometimes they work and not, apart from the directional and intermittent they do not work either, I assumed that there was some short in the cables, then it disarms the entire board to see the connections and follow the lines in case a burned cable was seen or something, but nothing. Everything looks good, except because I found many loose connections and I don't know if it's normal or open.



The cables also reach one as a plate where some squares are connected that are like relays, in the same place where the fuses go, then I would like to know if you know how the electrical system is to know if it is any of the squares that no longer serves or are the loose connections, or if they have any manual or diagram of the electrical system of the car, they would be appreciated very much. I attach photos.



I also found loose a little large connectors, in fact one had thick cables, as if it came from the battery, and brought tape to insulate and when I took it I saw that it brought a bridged wire. I attach some photos of those connections too.






Note: As I have already noticed, I don't know much about this, my turn is computer engineering, so I don't know cars, but I want to learn to not depend on the mechanics that are then well stained

Thanks comrades