Designing a remote starter

[CarAudioAddict]

okay here's the scoop.

I am designing a remote starter to run off the trunk pop option of my alarm.

I need to know if there is a wire in a 1985 GM vehicle that changes state when the engine has started and is running.

By changes state I mean goes:

from ground to NC
from NC to ground
from Hot to NC
from NC to Hot
from ground to hot (preferred)

[CarAudioAddict]

so I'm guessing no-one knows much about GM electrical Systems.

Would grounding a Relay through the voltage regulator damage it?
I have discovered that my alternator has a wire that changes from ground to hot when the engine starts, the problem is - this wire is controlled by the voltage regulator inside the alt.