does anyone know the wire i need to tap into to hook up a tach? has anyone had experience installing a tahc in there 2000ish jetta?

there is a speed signal wire in the interior dash wiring loom. it is a white/blue wire or a blue/white wire (can't remember at the mo..). it is picked up from the gbox speed sender. the speed signal wire goes to the radio, dashpod, relay plate, central convenience ecu, airbag ecu, abs ecu. this will give you the speed pulse thats required. you can pick up a live and earth locally somewhere.