which wire to see if car is 'on'

OK, I had my Autopage 855LCD alarm all wired up, and the brains died on me. So I unwired everything, and sent alarm back. Got the replacement in today. Now, before, I was able to program the different features, and everything was wired correctly (for this alarm, to program, you have to go on, off, on, off, on, off x number of times, then press valet switch x times). Right now I have to program the brains for my remote, but the unit is not recognizing that the car is being turned on. I don't know which wire I'm missing. So I'm wondering which wire does the alarm use to see if the car is on? I need to make sure that wire is in the right spot. Thanks, Kevin

Ahh, nevermind. It turns out one of the remote start outputs also doubles as an input to see when the car is on. I hadn't connected remote start yet. Connected and all works great :) Kevin