buick starter crank wire

I'm installing a remote starter .  The wiring chart for my 2006 Rendezvous lists the yellow wire in the ignition switch harness as the starter crank wire. Yet when I probe it while cranking there's nothing.  A small yellow wire in same harness shows 12 volts while cranking but it doesn't crank starter when I apply 12 volts to it directly from battery. Am I missing something?

did you have ignition switch turned on when you tried putting 12 volts on the smaller wire?

Actually, no I didnt. Never thought to. You think there's a starter disconnect relay in the circuit?God grant me the serenity to accept the things I cannot change, the courage to change the things I can, and the wisdom to know the difference.

most likely. that signal probally gotes to the pcm not directly to starter. so just the start signal alone does nothing

That makes sense. It explains why such a small wire would be adequate for the crank signal. The #10 guage wire from the remote starter made me think it had to connect to another large wire. I'll go ahead and connect to the small wire and post my results later . Thanks for your input.God grant me the serenity to accept the things I cannot change, the courage to change the things I can, and the wisdom to know the difference.