i have a 5inch tack but i don't know how to wire it up in my 95 neon?
I know where the red and black wire oviously go but where to i need to hook up the other wire?

You can find a aftermarket tachometer installation How-To for your car HERE. (http://www.neonspeed.com/howto/howto_1stgen_tachinstall.htm)

L8R,

Your car requires a converter box in order to pick up a signal from the coil pack!! You can buy the converter from Autometer! When you install the converter, cut the ground signal wire from the coil pack... You connect the wire you have cut and connect it to one of the wires going into the converter box, and the other wire coming out of the converter box connects back into the wire going to the coilpack!! basically all this does is extend the wire for the coil pack and send it through the converter box..... Next you connect the green wire (other wire) coming off the back of the tachometer to the third wire coming out of the converter box. (all the converter box does is read the number of times your spark plugs fire and translated that number into a signal that the tachometer can read). If you have any question feel free to e-mail me @ Drhorsefield@yahoo.com!!

P.S. there are two extremely small wires that loop out of the back of the tachometer... these are the only two wires that are not open ended... You will have to cut both of these wires so the tachometer reads correctly!!! Leave both uncut for 8 cyl., leave 1 uncut for 6 cyl., and cut both for 4 cyl. engines!!!