I just installed a tach and the thing won't read my rpm's. This is how I hooked it up:

Red: to cigarette lighter
Black: grnd on cigarette lighter
White: to dimmer switch
green: blue wire on dizzy

The tach lights up and it gets power to the connectors but it won't read rpm's.

What could it be?

 

I am assuming this is an autometer tach (if so) it needs to be calibrated. There are two wires on the back I think one is blue and the other is brown. You need to clip one to calibrate it. I belive it is the blue one.

 

you need to clip the brown and orange wires

 

Must be different for other models. I have a autometer c2 and there was a brown and blue wire. Any way it tells you in the instructions which ones to clip.

 

its not autometer. It's iEQUUS and I calibrated it accordind to the instructions. Could it be a faulty tach?

 

bump

 

what there saying is, you your self need to pick between 4-6-8 cylinders.by cliping the wires on say a autometer,you are then selceting how many cylinders for it to read.there may also be a hidden switch.

 

there is a switch in the back and that's how I calibrated to read 4 cylinders.

 

double check your wiring