So, I've been playing fallout 2, and I think I messed up hard. I made it to vault city, and after visiting a merchant I went right for the front gate. I thought because I had 9 INT I could smooth talk my way past the guards (like i did for the church in the Den) however after saying I forgot my papers, the guard told me to stop lying and come back when I had a day pass. I should note, I got there at night so Wallace wasn't in the customs office, and I didn't notice the locker in the corner. I went back to the guard and tried to ask where to get a day pass, but I thought since the first time I talked to her I could ask where it to get one after saying I was a citizen, that I could just say I'm a citizen again and ask her where to get a day pass. This was my folly. Apparently somehow this triggered me to get "banned" form the city by Lynette, despite never using the fake papers or entering the city at all. I got the day pass from the locker but the guards won't even initiate dialogue with me. I know this place isn't necessary to complete the main quest, but it just feels stupid to go anywhere else, and besides I don't rightly know any other way to find Vault 13. Anyway I can still get inside without completing the main quest?

EDIT: Forgot to mention that for some reason, Happy Harry (the merchant in the courtyard outside of VC) won't talk to me. All he says is "sorry can't help you neighbor" despite it being the correct time for him to be selling items.

Don't think you can get in when you first get banned, but you don't miss out on much other than the quest for the power plant in Gecko. And it's pretty easy to get banned by Lynette, so my advise is save often and use every save slot :)

There's at least one other way to find Vault 13 though.

*SPOILERS*

You get a quest for Vault 15 from Tandi in NCR. On Level 3 of V15, in the room opposite from the guy you're supposed to kill or negotiate with, there's a computer. You'll need a Science skill of 65 to use it and it will have info on V13.

You'll also need to get a Vault-Tec computer voice module from Eldridge in New Reno Arms since you can't get the one from Vault 8 in Vault City.

Hope this helps :)