Hi, how can I tell if my car is locked out so i can not program a new key to the system? Right now when I go through the whole process the first 2 steps go fine, when I goto do the 3rd step, it does nothing. The red security light just stays flashing.

 

Not sure about your Pacifica, but my Sebring will allow only 8 keys to be programmed. Do you know if somebody programmed a bunch of keys before you got it? I think that can be a problem with rental vehicles. People don't care about losing keys to a car they don't own.
I believe the dealer can tell if it's reached the limit by means of the DRB tool. That will cost you, however.