UPDATE! Its working, I had the tach and the light dimmer wires crossed. Seems odd they used a purple wire for the dimmer and a white wire for the tach lead to me /forums/images/graemlins/confused.gif Anyhow its all good. It kind of sucks though, its a 3 digital tach so if I'm running 1200 RPM its reads 120 (ie the first three numbers /forums/images/graemlins/tongue.gif) OH WELL! This works better then no tach! /forums/images/graemlins/whistling.gif OK I have a custom ground and the factory power block setups After hooking up the power the tach was on, so I pulled the power and placed it under the radio fuse I located the tach spade terminal (this is the right wire for the tach right?) I used a brown wire because its all I had long enough in the garage that wasn't black or red. I wired on the spade terminal and pushed it in. With the engine running the digital LED zeros just flash in random order... no numbers just zero's. Tach ideling short video Tach ideling long video (right click as target as... quicktime videos) /forums/images/graemlins/dunno.gif I tried the power wire under the power block and under the fuse, the zeros just kept flashing. Its a four wire hookup; red, black, purple and white. Red under radio fuse (keyed power) black is at the ground block purple has the brown extension wire going to the tach lead the white wire is not hooked up, I'm guessing its a dimmer for when the lights come on? Any ideas? I dont have the instructions. It came from jegs or summit, seems like its a cynden (sp?) digital tach. It was about $50 and its suppost to autosetup/autopickup for 4,6,8 cyl vehicles.