Board problem

Hello, I am Cochango de Neuquen, I am about to buy, a VW Polo Nafta Model 2000, the problem of it is that: when it contacts the board marks everything, lus and watches I perfect, when the board starts the board dies complete, it marks absolutely nothing, but the car is still working normal, they changed the plate of the board but still the same, what can the problem be? thank you

There to check the input current to the board and the land of the same, this to eat, because you cannot fail all the components of the car so that they do not mark a chrusada current.