I am trying to test my speed sensor ( the one on the harmonic balancer). I have a green , red , and black wire. I am trying to figure out where these wires go and what they do?

Also I am looking for the alt pulley size. Long story but I think I have the wrong pulley on my alt.

thanks

 

Only way I know of to test the ESS is with an oscilloscope.
All the wires from the ESS go to the PCM except the black ground wire.

 

k that sounds good now which on is the input and output?