But when you buy a new Kia, where do you find your account # to sign up for the Kia motor finance website? I had 2 other Kia's and so some reason I don't remember how I found my account #. My other Kia's are still on the site, I just want to add the new car. I just bought the car about 5 days ago. You would think they would use the same account # for all of your cars but they dont. I had different #'s for each of my cars but on the same login page. Am I just not waiting long enough for some welcome letter in the mail?