84 LeSabre Full Size GM wires

I need to know about the neutral saftey switch location on my LeSabre. I want to incoprporate it into my alarm as well as my aftermarket shifter. The diagram should be the same for other 80s b-bodies such as the Caprice or Delta 88. Also if someone could describe how this works I would be interested. I am assuming it just disconnects a couple wires if the shifter position is in a gear? Thanks in advance for the help.

Also, I have looked at the vehicle information DB and found this for my car: Neutral Safety Wire ORANGE / Black Engine Control Module But what/where is the Engine control module?

the e.c.m. on this vehicle should be behind the glove box

Thanks jerrykeenan. How does this wire control the ignition?

It's not so much that the wire controls the ign. but rather that when the N.S. switch is closed this allows current to pass through to the ign. sw. where otherwise it is interrupted. The N.S. is on top of the tranny where the linkage connects.