It depends on what modal you have. On pre 94 modals you simply just need to conect a wire to the brown LT wire closest to the grille on the coil. On later modals theres a conector at the back of the engine compartment behind a black plastic cover which covers the manifold heater relays and fuses. The conector has three wires coming in (blue, blue/white and brown/white) and two going out (blue, blue/white) The third wire (brown/white) is you thachometer wire.
This is all from memory but i used to work for FIAT and i have converted many standard dashboards to digital ones.
well i was redirected here to post my problem))so i have problem with my tachometer...i`m driving tipo 1,9TDI and the instroment panel is all digital everything works fine but the tacho just don`t work...actually i haven`t seen it working since i bought the car it wasn`t working then too.So my question is from where this tacho takes impulse to work i found that the speedometer takes from the gear box but i just can`t find the tacho...friends told me that it takes signal from the alternatore or whatever it is called in english)but i could not find the wires actually i saw two wires one for battery and the other from the battery to the alternatore:bang: )so any one can help me?)